The base-catalyzed cis-trans isomerization of cis and trans-alkyl 2-phenylcyclopropylcarboxylates was studied in several aprotic solvents. It was found that contact ion-pain of the derived carbanion lithium salts were configurationally more stable than the solvent-separated ones. Reaction of either the cis or the trans esters with MeI, and the reaction of the cis ester with Ph2C = O, resulted in the
在几种非质子溶剂中研究了碱催化的顺式和反式2-苯基环丙基
羧酸酯的顺式和反式异构化。发现衍生的碳负离子
锂盐的接触离子疼痛在结构上比溶剂分离的更稳定。任一的反应顺式或反式用MeI酯,以及所述的反应顺式的Ph酯2 C = O,导致在相应的具有I -取代的衍
生物的顺式仅几何。这被解释为是由于在反式底物的情况下对2-苯基施加的亲电子进攻的空间位阻。该反式酯不与Ph 2 C = O反应。所述的抑制反式-到-顺式的的负碳离子盐的异构化反pH值的存在基板2 C = O可能导致这样的结果。