Wittig-type Reaction of Dimetallated Carbodianion Species as Produced by Zinc Reduction of<i>gem</i>-Polyhalogen Compounds in the Presence of Lewis Acids
作者:Kazuhiko Takai、Yuji Hotta、Koichiro Oshima、Hitosi Nozaki
DOI:10.1246/bcsj.53.1698
日期:1980.6
Treatment of R1COR2 with a suspension prepared from diiodomethane, trimethylaluminum and excess zinc in tetrahydrofuran at room temperature affords olefins R1R2C=CH2 in fair (R1,R2=alkyl) to good (R1=alkyl, R2=H) yields. The ketone methylenation is better carried with another system consisting of CH2Br2–Zn–TiCl4. Ketones and aldehydes are transformed into α-chloro α,β-unsaturated esters or α,β-unsaturated
在室温下用由二碘甲烷、三甲基铝和过量锌在四氢呋喃中制备的悬浮液处理 R1COR2,以一般(R1,R2=烷基)到良好(R1=烷基,R2=H)产率提供烯烃 R1R2C=CH2。由 CH2Br2-Zn-TiCl4 组成的另一个系统可以更好地进行酮亚甲基化。在二乙基氯化铝和锌的存在下,用三氯乙酸甲酯或二氯乙酸叔丁酯(二溴乙酸乙酯)处理,酮和醛以良好的收率转化为 α-氯 α,β-不饱和酯或 α,β-不饱和酯。