Abstract
1,1-Dimethyl-2-trimethylsiloxyallyl chloride in the presence of 1,3-dienes gives seven-membered cyclic enones on treatment with silver perchlorate in yields of 85% with furan, 91% with cyclopentadiene, and 64% with isoprene, whereas the reaction with 2-methylfuran yields a mixture of two (5-methyl-2-furyl)butanone derivatives and two bicyclic enones.