Wittig-type reaction of dimetallated carbodianion species as produced by zinc reduction of gem-polyhalogen compounds in the presence of Lewis acids

K Takai, Y Hotta, K Oshima, H Nozaki

Index: Takai, Kazuhiko; Hotta, Yuji; Oshima, Koichiro; Nozaki, Hitosi Bulletin of the Chemical Society of Japan, 1980 , vol. 53, # 6 p. 1698 - 1702

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Citation Number: 141

Abstract

Treatment of R 1 COR 2 with a suspension prepared from diiodomethane, trimethylaluminum and excess zinc in tetrahydrofuran at room temperature affords olefins R 1 R 2 C= CH 2 in fair (R 1, R 2= alkyl) to good (R 1= alkyl, R 2= H) yields. The ketone methylenation is better carried with another system consisting of CH 2 Br 2–Zn–TiCl 4. Ketones and aldehydes are transformed into α-chloro α, β-unsaturated esters or α, β- ...