Sharpless asymmetric dihydroxylation as the key step in the enantioselective synthesis of spirocyclic σ1 receptor ligands
作者:Katharina Holl、Dirk Schepmann、Constantin Gabriel Daniliuc、Bernhard Wünsch
DOI:10.1016/j.tetasy.2013.12.009
日期:2014.2
The enantioselective synthesis of fluorinated spirocyclic σ1 ligands involved three key steps: (1) the Sharpless asymmetric dihydroxylation of 2-bromostyrene 5 provided enantiomerically pure diols (R)-6 and (S)-6 establishing the stereogenic center; (2) the intramolecular opening of the oxirane ring of (R)-11 and (S)-11, which occurred with excellent regioselectivity and complete inversion of configuration
氟化螺σ的对映选择性合成1个配体涉及三个主要步骤:(1)2-溴苯乙烯的Sharpless不对称二羟基化5提供对映体纯的二醇([R )- 6和(小号) - 6建立所述立体中心; (2)(R)-11和(S)-11的环氧乙烷环的分子内开口,具有极好的区域选择性和构型完全反转,从而可以得到对映体纯的醇(S)-7a和(R)-7a; (3)醇的处理(小号) -图7b和(- [R )-图7b用DAST,这就导致了氟甲基衍生物(小号) - 1和(- [R )- 1无外消旋作用。甲苯磺酸酯(R)-13的X射线晶体结构分析证实了螺环化合物的绝对构型以及5的Sharpless不对称二羟基化过程中的对映选择性。的(小号)构型氟甲基衍生物(小号) - 1揭示了高σ 1亲和力(ķ我 = 1.8纳米),高eudismic比(因子8)和高选择性在σ 2亚型(667倍)。