Enantioselective desymmetrisation of an epoxytropinone for peduncularine synthesis
作者:Ruth E. Shelton、Serdar Sezer、David M. Hodgson
DOI:10.1016/j.tet.2020.131701
日期:2020.12
A key 7-allyl-8-hydroxy-6-azabicyclo[3.2.1]octan-3-one intermediate in a synthesis of the alkaloid peduncularine is obtained enantioenriched, by desymmetrisation of an achiral 6,7-epoxy-8-azabicyclo[3.2.1]octan-3-one (epoxytropinone). Chiral lithium amide-assisted enantioselective silyl enol ether formation then TMSOTf/allyltrimethylsilane/2,6-lutidine-induced rearrangement−allylation proceeded in
通过非对称的非手性6,7-环氧-8-氮杂双环[[]]对称化获得生物碱peduncularine合成中的关键7-烯丙基-8-羟基-6-氮杂双环[3.2.1] octan-3-one中间体。 3.2.1] octan-3-one(环氧丁酮)。手性锂酰胺辅助的对映选择性甲硅烷基烯醇醚的形成,然后TMSOTf /烯丙基三甲基硅烷/ 2,6-二甲基吡啶诱导的重排-烯丙基化反应的进行时间高达80:20 er,但总收率不高。取代2,6-二甲基吡啶的手性胺或(硫代)脲直接从环氧肌酮中释放了76:24 er。使用BINOL衍生的双(磺酰基)酰亚胺催化剂和烯丙基三甲基硅烷进行的直接,简化(无碱)工艺证明是最有前途的(80%,83:17 er)。