Involvement of an Oxonium Ion Intermediate in Controlling the Diastereoselectivity of Nucleophilic Substitution Reactions of Septanoses
作者:Khoi B. Luu、K. A. Woerpel
DOI:10.1021/acs.orglett.2c03963
日期:2023.1.13
of septanoses control the stereochemical outcomes of O-glycosylation reactions of these seven-membered-ring intermediates. Isolation of a bicyclic acetal byproduct in some substitution reactions suggests that the C4 benzyloxy substituent engaged in long-range participation, stabilizing intermediates by the formation of an oxonium ion intermediate. Inductive destabilization of the carbocationic intermediate
七糖 C4 和 C2 处的烷氧基取代基控制这些七元环中间体的O-糖基化反应的立体化学结果。在一些取代反应中双环缩醛副产物的分离表明,C4 苄氧基取代基参与长程参与,通过形成氧鎓离子中间体来稳定中间体。 C2 取代基提供的碳阳离子中间体的诱导去稳定对于远程烷氧基的参与至关重要。