RHODIUM-STABILIZED VINYLCARBENOID INTERMEDIATES IN ORGANIC-SYNTHESIS

This article will give an overview of the reactions and synthetic util ity of rhodium-stabilized vinylcarbenoids, which have been shown in re cent years to be versatile synthetic intermediates. They undergo highl y diastereoselective cyclopropanations with a wide array of alkenes an d dienes, and the resulting vinylcyclopropanes are readily converted t o other ring systems. Most notable is the reaction between vinylcarben oids and dienes, which is a general method for the stereoselective con struction of seven-membered carbocycles by means of a tandem cycloprop anation/Cope rearrangement sequence. Efficient insertions into Si-H, C -H, NH and O-H bonds can also be achieved by rhodium-stabilized vinylc arbenoids. The synthetic utility of vinylcarbenoid chemistry has been greatly enhanced by the recent development of chiral catalysts and aux iliaries that enable this chemistry to be achieved,with high asymmetri c induction.