Since the pioneering work by Sarel and co-workers on the iron carbonyl p- moted transformation of vinylcyclopropanes and related compounds [1],a - riety of transition metal complexes have been examined to achieve effective - tivation of the vinylcyclopropane-cyclopentene rearrangement which usually requires pyrolytic conditions. These reactions have been applied to natural product synthesis in some cases and have already been reviewed in several - cellent articles [2-4]. Contrary to the well-established chemistry of the vinylcyclopropanes, the corresponding reactions of alkynyl- and propadienylcyclopropanes have not, until recently,received much attention.We present here a summary of the recent efforts towards the development of transition metal promoted transformation of these molecules with a brief survey of the corresponding thermal reactions. 2 Rearrangement of Alkynylcyclopropanols Unlike the well-known chemistry of the vinylcyclopropane-cyclopentene - arrangement, there is no general method for the rearrangement of alkyn- cyclopropane to cyclopentene derivatives.One specific example is the pyrolysis of 1-ethynyl-2-methylcyclopropane to methylenecyclopentene and other c- pounds [5]. At 530 C, 1-ethynyl-2-methylcyclopropane (1) undergoes a [1,- hydrogen shift to give hexa-1,2,5-triene ( 2),which further isomerizes to met- lenecyclopentenes 3 and 4 in 38 and 29% yield,respectively (Scheme 1).

Carbon Rich Compounds are defined here as carbon skeletons with a carbon-to-hydrogen ration of 1: (less than or equal 1), which includes all-carbon compounds, i.e. carbon allotrope. The current volume complements Topics in Current Chemistry Volume 196, which focussed on polycyclic aromatic compounds, by presenting an overview of the exciting recent results that have been achieved acetylene-based carbon rich structures. Leaders in the field present timely reviews on the synthesis, properties and chemistry of cyclic and macrocyclic oligoacetylenic structures, molecular scaffolding, arylene- and arylenevinylene-based oligomers and polymers, as well as carbon rich compounds from ethynylated Pi-complexes.

The topic .Stress and Strain. of this conference was ideally constrasted by the remoteness and quiet atmosphere of the meeting place Hotel Seehof In Ratzeburg, a small medieval town situated on a peninsula in lake "Kuchensee. east of Hamburg In northern Germany. With the participation of 53 leading experts from all over the world, the workshop covered the widest possible range from the advancement of bonding theory, new mechanistic insights into chemical transformations and physical properties of highly strained compounds to their use as building blocks In organic synthesis and even as probes Into the detection of enzyme mechanisms. Because of their specific reactivities small ring units can uniquely play their role in the construction of composite functionalities. Such functionalities can increase the elegance In natural and non-natural products syntheses, since they help to develop more convergent synthetic routes and Improve the necessary chemo-, regio-and stereo-selectivity. This book presents all of the 20 Invited lectures and is complemented with short versions of 12 contributed papers and 13 poster presentations. I am convinced that it will stimulate further rapid development of this field of organic chemistry, which recently has seen extensions into the bioorganic area as well as towards new materials. In fact, several .supra-natural" -at first sight exotic -compounds are already available In useful quantities and are being exploited to create vastly new molecular devices, i. e. compounds with unprecedented molecular functions and polymers with unconventional properties."

Carbon Rich Compounds are defined here as carbon skeletons with a carbon to hydrogen ratio of 1:(=

Carbon Rich Compounds are defined here as carbon skeletons with a carbon to hydrogen ratio of 1: (=centro"-polyhydrindanes as well as oligoquinanes, in particular highly unsaturated ones, are discussed.

More and more possible applications of organometallic compounds in organic synthesis have been uncovered and a growing number of scientists are attracted to this area of research. This book presents an state-of-the-art account of the successful application of main- and transition metal mediated syntheses. It will stimulate new ideas and initiate further research in all areas of this fascinating chemistry.

The topic ·Stress and Strain· of this conference was ideally constrasted by the remoteness and quiet atmosphere of the meeting place Hotel Seehof In Ratzeburg, a small medieval town situated on a peninsula in lake "Kuchensee· east of Hamburg In northern Germany. With the participation of 53 leading experts from all over the world, the workshop covered the widest possible range from the advancement of bonding theory, new mechanistic insights into chemical transformations and physical properties of highly strained compounds to their use as building blocks In organic synthesis and even as probes Into the detection of enzyme mechanisms. Because of their specific reactivities small ring units can uniquely play their role in the construction of composite functionalities. Such functionalities can increase the elegance In natural and non-natural products syntheses, since they help to develop more convergent synthetic routes and Improve the necessary chemo-, regio-and stereo-selectivity. This book presents all of the 20 Invited lectures and is complemented with short versions of 12 contributed papers and 13 poster presentations. I am convinced that it will stimulate further rapid development of this field of organic chemistry, which recently has seen extensions into the bioorganic area as well as towards new materials. In fact, several ·supra-natural" -at first sight exotic -compounds are already available In useful quantities and are being exploited to create vastly new molecular devices, i. e. compounds with unprecedented molecular functions and polymers with unconventional properties.