マグネシウムカルベノイドの転位反応を利用するβ、γ－不飽和エステル類の新規合成法

抄録

Addition reaction of 1-chlorovinyl p-tolyl sulfoxides, which were derived from various aldehydes,
with lithium enolate of tert-butyl acetate gave adducts in high yields. Magnesium carbenoids were generated by treatment of these adducts with Grignard reagents via the sulfoxide-magnesium exchange reaction. When the adducts were derived from alkyl aldehydes or electron-deficient aromatic aldehydes, b,g-unsaturated esters were obtained by 1,2-CH insertion reaction. On the contrary, when the adducts were derived from electron-rich aromatic aldehydes, b,g-unsaturated butyric esters were obtained by stereospecific 1,2-CC insertion reaction. When the addition reactions were quenched with iodoalkanes, tri-substituted b,g-unsaturated esters were obtained by the treatment of these adducts with EtMgCl. These procedure provide a good way for a new synthesis of b,g-unsaturated esters from aldehydes with two or three carbon-carbon bond-formations.