Synthesis of terpenes containing the bicyclo[3.1.1]heptane ring system by the intramolecular [2 + 2] cycloaddition reaction of vinylketenes with alkenes. Preparation of chrysanthenone, .beta.-pinene, .beta.-cis-bergamotene, .beta.-trans-bergamotene, .beta.-copaene, and .beta.-ylangene and lemnalol
Synthesis of terpenes containing the bicyclo[3.1.1]heptane ring system by the intramolecular [2 + 2] cycloaddition reaction of vinylketenes with alkenes. Preparation of chrysanthenone, .beta.-pinene, .beta.-cis-bergamotene, .beta.-trans-bergamotene, .beta.-copaene, and .beta.-ylangene and lemnalol
Submitting the title ketone to either acetoxymercuration or basic conditions resulted in the formation of the acid beta-5 and alpha-5, respectively, with an useful selectivity, related rearrangements being observed by using the corresponding alcohol and its epoxy derivative. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.