Asymmetric induction in addition of N-nitrenes to alkenes: 2-(chiral)substituted benzimidazole-derived N-nitrene additions to alkenes
作者:Robert S. Atkinson、Gary Tughan
DOI:10.1039/p19870002787
日期:——
Oxidation of the optically active 1-aminobenzimidazoles (5)–(7) with lead tetra-acetate in the presence of various prochiral alkenes yields mixtures of the diastereoisomeric aziridines with little asymmetric induction (Table). Oxidation of theracemic 1-amino-2-(1,2,2-trimethylpropyl)-1H-benzimidazole (12) in the presence of α-methylene-γ-butyrolactone (1) yields the stereoisomeric azirid (16) in a
在各种前手性烯烃的存在下,用四乙酸铅氧化旋光的1-氨基苯并咪唑类化合物(5)-(7),得到的非对映异构氮丙啶混合物几乎没有不对称诱导(表)。在α-亚甲基-γ-丁内酯(1)存在下,对外消旋的1-氨基-2-(1,2,2-三甲基丙基)-1 H-苯并咪唑(12)的氧化在5.5中产生立体异构的叠氮基(16)比率为1:1,并且在存在γ,γ-二甲基-α-亚甲基-γ-丁内酯(18)时发生氧化,立体定向形成氮丙啶(19)。(19)的立体化学由X决定。射线晶体学。