It was a great honor for us to organize ChiCat, a symposium devoted to Chiral Reactions in Heterogeneous Catalysis and to be the hostsofmore than 120 scientists coming from everywhere in the industrialized world, to celebrate together one century of existence ofInstitut Meurice. This school was established in 1892when an industrial chemist, named Albert Meurice, decided to educate practical chemists according to the perceived needs ofthe industry ofthat time. This is exactly what we are still trying to do. It is the reason why, thirty years ago, we started a research activity in catalysis, and why we progressively devote this research to the applications of catalysis in the field of fine chemicals. In this respect, we are very close to another initiative of Albert Meurice, who started the first production of synthetic pharmaceuticals in Belgium during World War I. This business later on became a part ofthe Belgian corporation DCB, still very active in pharmaceuticals today. The school created by Albert Meurice merged in the fifties with another school that had been created to meet the same needs in the field of the food industries, mainly distilleries and breweries. This merger was done in the frame of the establishment of CERIA. For people in catalysis, ceria stands for cerium oxide, but for those who engineered the concept, CERIA stood for Center of Education and Research for the Food and Chemical Industries.

1. INTRODUCTION Although quite spectacular results have been obtained in the last few decades in the field of homogeneous transition metal catalyzed transformations of olefins and alkynes [1], reactions which could lead to heterocycles have been partly neglected. An obvious reason for this is that substrates containing heteroatoms such as N, 0 or S could coordinate the metal and suppress the catalytic activity. Nevertheless, some interesting early examples of transition-metal-catalyzed syntheses of heterocyclic compounds have been reported and these have been reviewed by C. W. Bird [2] . More recently the incorporation of CO , which enables esters and lactones 2 to be synthesized from olefinic starting materials, has begun to attract attention (see, for example, ref. [3]). The dominant role of palladium as the catalyst for the formation of O-containing heterocycles has been suggested to be associated with the relatively low strength of the Pd-O bond. Among the first examples of a nitrogen-containing heterocycle to be formed by homogeneous catalysis is the triazine shown in Equation 1 which is the product of the trimerization of benzonitrile in the presence of iron penta carbonyl or Raney nickel [4] .

Enzymes perform the executive role in growth, energy conversion, and repair of a living organism. Their activity is adjusted to their en vironment within the cell, being turned off, switched on, or finely tuned by specific metabolites according to demands at the physiologi cal level. Each enzyme discovered in the long history of enzymology has revealed its own individuality. Even closely related members of a family differ in specificity, stability or regulatory properties. Despite these, at first sight overwhelming aspects of individuality, common factors of enzymic reactions have been recognized. Enzymes are stereospecific catalysts even when a nonspecific process would yield the same product. Knowledge of the detailed stereochemistry of an enzymic reaction helps to deduce reaction mechanisms and to ob tain insight into the specific binding of substrates at the active site. This binding close to catalytically competent groups is related to the enormous speed of enzyme-catalyzed reactions. The physical ba sis of rate-enhancement is understood in principle and further exploit ed in the design of small organic receptor molecules as model enzymes. These aspects of enzyme catalysis are discussed in Session 1. Session 2 emphasizes the dynamic aspects of enzyme substrate inter action. Substrate must diffuse from solution space to the enzyme's surface. This process is influenced and can be greatly facilitated by certain electrostatic propterties of enzymes. The dynamic events during catalysis are studied by relaxation kinetics or NMR techniques."

There are only few topics in organometallic chemistry, which have stimulated research activities in as many areas, as transition-metal carbene (alkylidene) complexes. About 25 years after the first planned synthesis of a carbene complex in E.O. Fischer's laboratory in Munich the NATO Advanced Research Workshop on Transition-Metal Carbene Complexes was the first meeting which, brought together scientists from different disciplines to discuss inorganic, organic, theoretical structural catalysis-related aspects of metal carbene chemistry. The 70th birthday of Professor E.O. Fischer was a good occasion for this enterprise. The organizers of the meeting (K.D. Dotz, Marburg; F.R. KreiBl, Munchen; U. Schubert, Wurzburg) were encouraged by the fact that most of the leading scientists in this area were able to participate in the workshop. The very high standard of the contributions is reflected in this book, which contains papers from the majority of the participants. The Proceedings show the state of the art in metal carbene chemistry and will hopefully be a landmark in the development of this area of chemistry. Generous financial support for the workshop and for the preparation of this book was provided by the Scientific Affairs Division of NATO and some companies. The organizers also acknowledge the efforts of the staff of the Bildungs zentrum der Hans-Seidel-Stiftung in Wild bad Kreuth for creating a pleasant and stimulating atmosphere during the conference."

Barry Trost: Transition metal catalyzed allylic alkylation.- Jeffrey W. Bode: Reinventing Amide Bond Formation.- Naoto Chatani and Mamoru Tobisu: Catalytic Transformations Involving the Cleavage of C-OMe Bonds.- Gregory L. Beutner and Scott E. Denmark: The Interplay of Invention, Observation and Discovery in the Development of Lewis Base Activation of Lewis Acids for Catalytic Enantioselective Synthesis.- David R. Stuart and Keith Fagnou: The Discovery and Development of a Palladium(II)-Catalyzed Oxidative Cross-Coupling of Two Unactivated Arenes.- Lukas Goossen and Kathe Goossen: Decarboxylative Cross-Coupling Reactions.- A. Stephen K. Hashmi: Gold-Catalyzed Organic Reactions.- Ben List: Developing Catalytic Asymmetric Acetalizations.- Steven M. Bischof, Brian G. Hashiguchi, Michael M. Konnick, and Roy A. Periana: The De NovoDesign of CH Bond Hydroxylation Catalysts.- Benoit Cardinal-David, Karl A. Scheidt: Carbene Catalysis: Beyond the Benzoin and Stetter Reactions.- Kenso Soai and Tsuneomi Kawasaki: Asymmetric autocatalysis of pyrimidyl alkanol.- Douglas C. Behenna and Brian M. Stoltz: Natural Products as Inspiration for Reaction Development: Catalytic Enantioselective Decarboxylative Reactions of Prochiral Enolate Equivalents. Hisashi Yamamoto: Acid Catalysis in Organic Synthesis.

Organic chemistry is constantly concerned with effecting reactions at a particular centre in a complex molecule, and if possible with a high and predictable level of stereoselectivity. In the light of much accumulated ex perience within organic chemistry it is usually possible to assess the likeli hood of alternative reaction pathways at least qualitatively. However, well based expectations can be falsified, and the experiments directed to the synthesis of vitamin B12 which led to Woodward's recognition of orbital symmetry control in organic chemistry are an instructive example. Our limi tations in this respect are very much accentuated in the case of hetero geneous reactions, which present additional problems, and except for very well studied instances, heterogeneous catalysis has remained a relatively empirical area of chemistry. Knowledge in this area has, however, been greatly improved by the development of transition metal complexes which replicate the catalytic properties of the metals, and are effective in a homo geneous reaction system. This development has advanced our understanding of catalysis by making it possible to interpret reactions in strictly molecular terms. In addition, these homogeneously active complexes are frequently more selective than their heterogeneous metallic counterparts either in discriminating between different functional centres in a molecule or in of fering better stereoselectivity. Homogeneous catalysts have now been devised for a number of organic chemical reactions, including hydrogenation, carbonylation, polymerisa tion, and isomerisation and dismutation of alkenes."

Catalysts are now widely used in both laboratory and industrial-scale chemistry. Indeed, it is hard to find any complex synthesis or industrial process that does not, at some stage, utilize a catalytic reaction. The development of homogeneous transition metal catalysts on the laboratory scale has demonstrated that these systems can be far superior to the equivalent heterogeneous systems, at least in terms of selectivity. is an increasing interest in this field of research from both an Thus, there academic and industrial point of view. In connection with the rapid developments in this area, four universities from the E.E.C (Aachen, FRG; Liege, Belgium; Milan, Italy; and Lille, France) have collaborated to organise a series of seminars for high-level students and researchers. These meetings have been sponsored by the Commission of the E.E.C and state organizations. The most recent of these meetings was held in Lille in September 1985 and this book contains updated and expanded presentations of most of the lectures given there. These lectures are concerned with the field of homogeneous transition metal catalysis and its application to the synthesis of organic intermediates and fine chemicals from an academic and industrial viewpoint. The continuing petroleum crisis which began in the early 1970s has given rise to the need to develop new feedstocks for the chemical industry.

The field of organometallic chemistry has emerged over the last twenty-five years or so to become one of the most important areas of chemistry, and there are no signs of abatement in the intense current interest in the subject, particularly in terms of its proven and potential application in catalytic reactions involving hydrocarbons. The development of the organometallic/ catalysis area has resulted in no small way from many contributions from researchers investigating palladium systems. Even to the well-initiated, there seems a bewildering and diverse variety of organic reactions that are promoted by palladium(II) salts and complexes. Such homogeneous reactions include oxidative and nonoxidative coupling of substrates such as olefins, dienes, acetylenes, and aromatics; and various isomerization, disproportionation, hydrogenation, dehydrogenation, car bonylation and decarbonylation reactions, as well as reactions involving formation of bonds between carbon and halogen, nitrogen, sulfur, and silicon. The books by Peter M. Maitlis - The Organic Chemistry of Palladium, Volumes I, II, Academic Press, 1971 - serve to classify and identify the wide variety of reactions, and access to the vast literature is available through these volumes and more recent reviews, including those of J. Tsuji [Accounts Chem. Res. , 6, 8 (1973); Adv. in Organometal. , 17, 141 (1979)], R. F. Heck [Adv. in Catat. , 26, 323 (1977)], and ones by Henry [Accounts Chem. Res. , 6, 16 (1973); Adv. in Organometal. , 13, 363 (1975)]. F. R. Hartley's book - The Chemistry of Platinum and Palladium, App!. Sci. Pub!.

New Trends in Enzyme Catalysis and Biomimetic Chemical Reactions embraces modern areas of enzyme catalysis where other books in the field concentrate mainly on kinetic, bioorganic and biochemical aspects of the enzyme catalysis and do not cover biophysical and physicochemical problems. Topics covered include:

-modern physical and kinetic methods of investigation,
-contemporary theories of elementary chemical processes in enzymes,
-structure, dynamics and action mechanism of enzyme active sites,
-concept of pretransition state,
-theory of long-range electron transfer and proton translocation,
-mechanisms of "tough" biochemical reactions (dinitrogen reduction, light energy conversation, water photooxidation, hydroxilation),
-the achievements and problems of biomimetic chemical reactions.

Well tailored metal catalysts are catalysts of the new generation resulting from scientific development at the boundary between homogeneous and hetero- geneous chemistry. The main factors involved in making tailored metal catalysts are not those of traditional impregnation in which the chemistry is in general unknown and ill-defined, or of simple ion exchange which involves long-range forces with little control on the local structure through definite and special bond direction. Tailored Metal Catalysts thus has a rather different emphasis from normal review publications in the field of catalysis. Here we concentrate more on the distinct surface chemistry and catalytic properties of important established materials with well-characterized active structures or precursors, although at the same time providing a systematic presentation of relevant data. Many pioneering works have been undertaken in the field of tailored metal catalysts since the early research on polymer-attached homogeneous metal complexes by the British Petroleum Company Ltd. and the Mobil Oil Corpora- tion around 1969; transition metal complexes attached on polymers by Grubbs (1971), Heinemann (1971), Manassen (1971), Pittman (1971), Bursian et al. (1972), Kagan (1973), Bailar (1974); transition metal complexes attached on inorganic oxides by Allum et al. (1972), Ballard (1973), Candlin and Thomas (1974), Murrell (1974), Yermakov (1974); metal carbonyls/polymers by Moffat (1970); metal carbonyls/inorganic oxides by Parkyns (1965), Davie et al. (1969), Banks et al. (1969), Howe (1973), Burwell (1975); metal carbonyl clusters/ polymers by Colhnan (1972); metal carbonyl clusters/inorganic oxides by Robertson and Webb (1974), Anderson (1974), Smith et al. (1975).

Organic chemistry has played a vital role in the development of diverse molecules which are used in medicines, agrochemicals and polymers. Most ofthe chemicals are produced on an industrial scale. The industrial houses adopt a synthesis for a particular molecule which should be cost-effective. No attention is paid to avoid the release of harmful chemicals in the atmosphere, land and sea. During the past decade special emphasis has been made towards green synthesis which circumvents the above problems. Prof. V. K. Ahluwalia and Dr. M. Kidwai have made a sincere effort in this direction. This book discusses the basic principles of green chemistry incorporating the use of green reagents, green catalysts, phase transfer catalysis, green synthesis using microwaves, ultrasound and biocatalysis in detail. Special emphasis is given to liquid phase reactions and organic synthesis in the solid phase. I must congratulate both the authors for their pioneering efforts to write this book. Careful selection of various topics in the book will serve the rightful purpose for the chemistry community and the industrial houses at all levels. PROF. JAVED IQBAL, PhD, FNA Distinguished Research Scientist & Head Discovery Research Dr. Reddy's Laboratories Ltd.

Continuously increasing oil prices, a dwindling supply of petroleum, and the existence of extensive reserves of biomass, especially of coal, have given rise to a growing interest in generating CO/H from these sources. Catalytic reactions can 2 convert CO/H mixtures to useful hydrocarbons or hydrocarbon intermediates. 2 There is little doubt that petroleum will remain the backbone of the organic chemical industry for many years to come, yet there is great opportunity for CO as an alternative feedstock at times when it is needed. The loosely defined body of chemistry and technology contained in these areas of development has become known as C 1 chemistry, embracing many C 1 building blocks such as CH , CO/H , CO, CH OH, CO and HCN; still emphasis 4 2 3 2 rests on carbon monoxide. Academic research laboratories, oil and chemical companies are in the vanguard of C 1 chemistry. The Japanese Ministry of International Trade and Industry is sponsoring a seven-year program of 14 major chemical companies in C 1 chemistry aimed at developing new technology for making basic chemicals from CO and H2 . It is likely that C 1 chemistry will develop slowly but persistently and the future holds great potential.

It is now IS years since the first patents in polymer supported metal complex catalysts were taken out. In the early days ion-exchange resins were used to support ionic metal complexes. Soon covalent links were developed, and after an initially slow start there was a period of explosive growth in the mid to late 1970s during which virtually every homogeneous metal complex catalyst ever reported was also studied bound to a support. Both polymers and inorganic oxides were studied as supports, although the great preponderance of workers studied polymeric supports, and of these polystyrene was by far the commonest used. This period served to show that by very careful design polymer-supported metal complex catalysts could have specific advantages over homogeneous metal complex catalysts. However the subject was a complicated one. Merely immobilising a successful metal complex catalyst to a functionalised support rarely yielded other than an inferior version of the catalyst. Amongst the many discouraging results of the 1970s, there were more than enough results that were sufficiently encouraging to demonstrate that, by careful design, supported metal complex catalysts could be prepared in which both the metal complex and the support combined together to produce an active catalyst which, due to the combination of support and complex, had advantages of activity, selectivity and specificity not found in homogeneous catalysts. Thus a new generation of catalysts was being developed.

The continually growing contribution of transition metal chemistry to synthetic organic chemistry is, of course, widely recognized. Equally well known is the difficulty in keeping up-to-date with the multifarious reactions and procedures that seem to be spawned at an ever-increasing rate. These can certainly be summarized on the basis of reviews under the headings of the individual transition metals. More useful to the bench organic chemist, however, would be the opposite type of concordance based on the structural type of the desired synthetic product. This is the approach taken in the present monograph, which presents for each structural entity a conspectus of the transition metal-mediated processes that can be employed in its production. The resulting comparative survey should be a great help in devising the optimum synthetic approach for a particular goal. It is presented from an essentially practical viewpoint, with detailed direc tions interspersed in the Houben-Weyl style. The wide scope of the volume should certainly encourage synthetic organic chemists to utilize fully the range and versatility of these transition metal-mediated processes. This will certainly be a well-thumbed reference book R. A. RAPHAEL Cambridge University v Preface In recent years an enormous amount of work has been done on the catalysis of organic reactions by various transition metal species and on the organic reactivity of organo-transition-metal compounds."

The literature contains tens of thousands of publications and patents devoted to the synthesis, characterization and processing of polymers. Despite the fact that there are more than one hundred elements, the majority of these publications and patents concern polymers with carbon backbones. Furthermore, the limited (by comparison) number of publications on polymers that contain elements other than carbon in their backbones are typically devoted to polymers based on silicon, especially those with Si-O bonds. This disparity is partially a consequence of the dearth of low cost organometallic feedstock chemicals potentially useful for polymer synthesis. It also derives from the lack of general synthetic techniques for the preparation of organometallic polymers. That is, by comparison with the numerous synthetic strategies available for the preparation of organic polymers, there are few such strategies available for synthesizing tractable, organometallic polymers. In recent years, commerical and military performance requirements have begun to challenge the performance limits of organic polymers. As such, researchers have turned to organometallic polymers as a possible means of exceeding these limits for a wide range of applications that include: (1) microelectronics processing (e.g. photoresists) [1]; (2) light weight batteries (conductors and semi-conductors) [2]; (3) non-linear optical devices [3] and, (4) high temperature structural materials (e.g. ceramic fiber processing) [4,5].

Some years ago, I agreed to contribute a volume to the Academic Press 'Organo metallic Chemistry' series - the metals to be covered were rhodium and iridium. Initially, my plan was to discuss both the fundamental organometallic chemistry and applications in organic synthesis. When the first draft of the manuscript was complete, it was apparent that I had exceeded my allowance of pages by a huge amount. It was then that I decided that the catalysis section warranted separate treatment. I am grateful to Reidel for agreeing to publish this volume on Homogeneous Catalysis with Compounds of Rhodium and Iridium as part of their 'Catalysis by Metal Complexes' series. The material I had for the original Academic Press project covered the litera ture to the end of 1978. I decided to update this to the end of 1982 with a few key references from 1983. It is some measure of the rate of progress in this field that the number of references almost doubled during this revision."

Another approach is via the peracid route [10,Il], whereby propylene is epoxidized by an organic peracid, usually peracetic acid. The latter is prepared either by reaction of acetic acid with hydrogen peroxide, or by autoxidation of acetaldehyde. - (3) - (4) ---I...MeC0 H MeCHO +02 3 /'\. (5) MeC0 H + MeCH=CH ---I ...MeCH-CH + MeC0 H 3 2 2 2 Although this method has been extensively studied [10, II] and is often the method of choice for laboratory scale preparations of epoxides, it has not been widely applied on a commercial scale. The reasons are probably to be found in the hazards associated with the handling of these explosive and corrosive peracids on an industrial scale. Nevertheless, several companies continue to groom this method for future commercialization [12]. With organic hydroperoxides becoming available as commercial chemicals, in the last decade propylene oxide process technology has seen the commercializa- tion of the hydroperoxide route. Such a process, developed by Halcon Interna- tional and Atlantic Richfield, is that often referred to as the Halcon or Oxirane process [13]. It involves the reaction of propylene with an alkyl hydroperoxide in the presence of a soluble, metal catalyst (usually a molybdenum compound). The alkyl hydroperoxide is prepared by autoxidation of an appropriate hydro- carbon. For example, tert-butyl hydroperoxide (TBHP) is prepared by autoxida- tion of isobutane. (6) Reaction with propylene gives propylene oxide and tert-butanol as a coproduct.

In recent years, the liquid phase oxidation of organic substrates using transition metal compounds as catalysts has become a profitable means of obtaining industrially important chemicals. Millions of tons of valuable petrochemicals are produced in this manner annually [1]. Typical examples of such processes are the production of vinyl acetate or acetaldehyde via the Wacker process, equations (1) and (2); the Mid Century process for the oxidation of methyl aromatics, such as p-xylene to tereph thalic acid, equation (3); and the production of propylene oxide from propylene using alkyl hydroperoxides, equation (4). PdCI , CuCI 2 2 (1) CH2 = CH2 + 1/2 O2 -H 0 ~ CH3CHO 2 (2) Co(OAcjz ~ (3) (4) The vast majority of liquid phase transition metal catalyzed oxidations of organic compounds fall into these three broad categories: (a) free radical autoxidation reactions, (b) reactions involving nucleophilic attack on coordinated substrate such as the Wacker process, or (c) metal catalyzed reactions of organic substrates with hydroperoxides. Of these three classes of oxidations only the first represents the actual interaction of dioxygen with an organic substrate. The function of oxygen in the Wacker process is simply to re-oxidize the catalyst after each cycle [2].

Soluble catalysts are used extensively in many branches of chemistry and are indeed a vital constituent of many natural processes. They find wide application throughout the chemical industry where they assist in the production of several million tonnes of chemicals each year. Since homogeneous systems, especially those incorporating transition metals, often function effectively under milder conditions than their heterogeneous counterparts, they are becoming increasingly important at a time when the chemical industry in particular, and society in general, is seeking ways of conserving energy and of making the best possible use of available resources. My principal objective in- writing this book is to engender sufficient enthusiasm for, and knowledge of, the subject in the reader that he or she will be encouraged to begin, or continue, to make their own contribution to advancing our knowledge of homogeneous catalysis. After attempting to acquaint the reader with some of the ground rules I have tried to describe the present scope, and the future potential, of this fascinating field of chemistry by drawing both on academic and on industrial data sources. This approach stems from a personal conviction that future progress could be considerably hastened by a more meaningful dialogue between chemists working both in industrial and in academic research institutions. Wherever possible, examples of the commercial application of homogeneous catalyst systems have been included and no attempt has been made in any way to disguise the many unresolved questions and exciting challenges which still pervade this rapidly developing area.

The rate of advance in areas of science is seldom constant. Usually certain fields effloresce with activity because of the ealization that solutions are possible to long standing important problems. So it is now with asymmetric catalysis, a field which promises to change profoundly the strategic thinking of synthetic chemists. As this Report will show, reagents which can induce catalytic enantiocontrol of chemical transformations could represent the ultimate synthetic method. Nearly all synthetic strategies of complex molecules involve steps which require enantiocontrol and, in many cases, a specific catalytic transformation embodying enan tiocontrol has enormous advantages in terms of the rate and economy of the reaction. Because asymmetric catalysis is in a formative stage, workers with different backgrounds have joined the field. This Workshop had representatives with organometallic, organic, structural, kinetic, enzymatic, microbiological and industrial backgrounds. Each had his own perspective and this Report represents a consensus of this group of eleven people. The result is probably as compre hensive and balanced a view of the subject as is possible at present. It is hoped that those who have until now had but a glancing interest in asymmetric catalysis will find this Report a useful indication of its present state. We believe that asymmetric catalysis will have an increasing impact on the development of chemistry and will eventually dominate much of synthetic and industrial chemistry."

The field of petrochemicals started some years ago with the simple addition reaction of water to propylene for the production of isopropyl alcohol. Currently, the petrochemical industry has become a multi-billion dollar enterprise which encompasses a wide field of chemical products. Almost all the basic organic reactions such as hydrogenation, alkylation, substitution, polymerization, etc. are utilized for the production of these chemicals. It may not, however, have been possible to establish this huge industry without the use of different catalysts. In other words, the great advancements in the catalytic area have supported the vast developments in the petrochemical field. In this book, we have adopted the idea of discussing the petrochemical industry from the point of view of reactants' activities and susceptibilities toward different catalysts. The book is thus classified according to the reaction type. This will eriable students and other users of the book to base their understanding of the petrochemical field on the fundamental principles learned in chemistry. How ever, the first chapter is aimed at establishing some basic facts on the petro chemical industry and its major uses. It discusses, without going into details, the raw materials used, the intermediates and the downstream products. The next eight chapters discuss in some detail the main reactions and the catalysts used for the production of chemicals and polymers from petroleum. The last chapter is devoted to a discussion of some of the practical techniques used in the catalytic field."

As nucleophiles, simple alkenes are typically so unreactive that only highly active electrophiles, such as carbocations, peroxides, and halogens will react with them. For the generation of carbon-carbon bonds, milder methods will often be required. Fortunately, it is possible to increase the reactivity of alkene-type p-nucleophiles by introducing electron-donating substituents. Substitution of one H with an OH or OR gives an enol or a vinyl ether, which are already much better nucleophiles. Using nitrogen instead of oxygen, one obtains even better nucleophiles, enamines. Enamines are among the most reactive neutral carbon nucleophiles, exhibiting rates that are even comparable to some charged nucleophiles, such as enolates [1, 2]. Most enamines, unfortunately, are sensitive to hydrolysis. The parent enamine, N,N-dimethylvinylamine, has in fact been prepared [3], but appears to be uns- ble. Enamines of cyclic ketones and many aldehydes can readily be isolated, however [4-7]. The instability of enamines might at first appear to diminish the utility of enamines as nucleophiles, but actually this property can be viewed as an added benefit: enamines can be readily and rapidly generated catalytically by using a suitable amine and a carbonyl compound. The condensation of aldehydes or ketones with amines initially affords an imine or iminium ion, which then rapidly loses a proton to afford the corresponding enamine (Scheme 1).

Proceedings of the NATO Advanced Study Institute on New Trends and Applications of Photoelectrochemistry and Photocatalysis for Environment Problems, Cafelu, Palermo, Italy, September 6-18, 1987

The origins of the petrochemical industry can be traced back to the 1920s when simple organic chemicals such as ethanol and isopropanol were first prepared on an industrial scale from by-products (ethylene and propylene) of oil refining. This oil-based petrochemical industry, with lower olefms and aromatics as the key building blocks, rapidly developed into the enormous industry it is today. A multitude of products that are indispensible to modern day society, from plastics to pharmaceuticals, are derived from oil and natural gas-based hydro carbons. The industry had its heyday in the '50s and '60s when predictions of future growth rates tended to be exponential curves. However, two developments that took place in the early '70s disturbed this simplistic and optimistic view of the future. Firstly, the publication of the report for the Cub of Rome on the 'Limits to Growth' emphasized the finite nature of non-renewable fossil fuel resources. Secondly, the Oil Crisis of 1973 emphasized the vulnerability of an energy and chemicals industry that is based largely on a single raw material."