Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA.
Org Lett. 2010 Oct 15;12(20):4694-7. doi: 10.1021/ol102142a.
Chiral nonracemic γ-seleno-α,β-ethylenic esters, when treated with sulfuryl chloride and ethyl vinyl ether in hexanes, produced α-chloro-β,γ-ethylenic esters in 65-75% yields, with ee values of 95-97%, and with 1,3-syn transfer of chirality. Reaction of these allylic chloride electrophiles with methylcuprate and with sodium azide nucleophiles afforded exclusively γ-substituted-α,β-ethylenic esters with faithful anti-transfer of chirality on multigram scale.
手性非外消旋 γ-硒代-α,β-烯基酯在正己烷中用氯化亚砜和乙烯基乙醚处理,生成 α-氯-β,γ-烯基酯,产率为 65-75%,ee 值为 95-97%,并且具有 1,3-顺式手性转移。这些烯丙基氯亲电试剂与甲基铜试剂和叠氮化钠亲核试剂反应,仅在毫克级规模上以忠实的反式手性转移得到γ-取代-α,β-烯基酯。