作者:Jean Villieras、Cathy Bacquet、Jean F. Normant
DOI:10.1016/s0022-328x(00)89303-1
日期:1975.9
warming, either by α-elimination of ClLi or β-elimination of ROLi. β-Elimination is generally observed and leads to the formation of a dichloroalkene which reacts with excess of butyllithium (or lithium dialkylamide) to give the corresponding mono-substituted alkyne (or chloroalkyne) with good yields. α-Elimination is followed by the migration of a group from the alcoholic carbon to the carbenoid center;
在低温(-100°C)下稳定的β-烷氧基和-甲硅烷氧基α,α-二氯卡宾类化合物在升温时会通过α-消除ClLi或β-消除ROLi迅速分解。通常观察到β-消除,并导致形成二氯烯烃,其与过量的丁基锂(或二烷基酰胺锂)反应,以良好的收率得到相应的单取代炔烃(或氯炔烃)。α-消除后,一个基团从醇碳迁移到类胡萝卜素中心。由此形成烷基(或三甲基甲硅烷基)α-氯乙烯基醚。甲硅烷基衍生物进一步被过量的金属化剂裂解成醛或酮的碱金属α-氯烯酸酯。当空间位阻阻止任何合成或合成时,总是观察到LiCl的α消除参与β消除的两组(Ro-Li)的抗构象。因此,当庞大的三甲基甲硅烷氧基导致α-消除时,其被甲氧基取代得到β-消除的产物。