New Cationic Olefin Cyclization−Pinacol Reactions. Ring-Expanding Cyclopentane Annulations That Directly Install Useful Functionality in the Cyclopentane Ring
作者:Larry E. Overman、John P. Wolfe
DOI:10.1021/jo025927r
日期:2002.9.1
cycloalkanone is ring-expanded and fused to a 2-alkenylcyclopentane fragment. Reaction of cis-(2-siloxy-2-alkenylcycloalkyl)pyrrolidin-1-ylethanones 15-17 with triflic anhydride and 2,6-di-tert-butyl-4-methylpyridine (DTBMP) at -20 to +65 degrees C followed by hydrolysis of the intermediate iminium salts 64 with aqueous KHCO(3) affords cycloalkanediones 46-48 in moderate yield and high diastereoselectivity