K. Matsui, A. Negishi, Y. Takahatake
1986
Citations
0
Influential Citations
10
Citations
Journal
Bulletin of the Chemical Society of Japan
Abstract
A synthesis of the title compounds 5 involves the reaction between 3-methyl-2-buten-1-ol and triethyl orthoacetate to produce ethyl 3,3-dimethyl-4-pentenoate, which is followed by the addition of various carbon tetrahalides to the double bond. The reaction of resulting adducts with a base affords 5 in high yields. Stereoselective preparation of the cis-isomer was achieved by the following two methods: First one involves selective transformation of ethyl 4-bromo-6,6,6-trichloro-3,3-dimethylhexanoate to ethyl 6,6,6-trichloro-3,3-dimethyl-4-hexenoate (8a) with piperidine followed by the selective conversion of 8a to cis-2,2-dichloroethenyl compound (cis-5a). Second one is based on the stereoselective cyclization of ethyl 4,6,6,6-tetrachloro-3,3-dimethylhexanoate (t-BuONa/solvent/HMPA) to ethyl cis-2,2-dimethyl-3-(2,2,2-trichloroethyl)cyclopropanecarboxylate which is transformed into cis-5a without cis-trans isomerization.