EFFICIENT INTRAMOLECULAR C-H INSERTION BY AN ALKYLIDENE CARBENE GENERATED FROM A VINYL CHLORIDE

摘要

It is observed that chloride 4 on exposure to sodium bis(trimethylsilyl)amide smoothly generates the cyclopentene 5, by insertion of the intermediate alkylidene carbene into the methine C-H. Chloride 4 is prepared in several steps from L-tartaric acid. On ozonolysis and subsequent aldol condensation, 5 is transformed into 1, a synthon for the A ring of taxol 2. [References: 53]