A Convenient Synthesis of Ethyl 3-(2,2-Dihaloethenyl)-2,2-dimethylcyclopropanecarboxylates and Its Modifications for cis-Isomer Enrichment
Year: 1986
Type: article
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.
DOI: 10.1246/bcsj.59.221
Authors: Kiyohide Matsui, Akira Negishi, Yuriko Takahatake, Kikuo Sugimoto, Tamotsu Fujimoto, Toshiyuki Takashima, Kiyosi Kondo
Institution: Sagami Chemical Research Institute
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2004705991