Iterative Stereospecific Reagent-Controlled Homologation Using a Functionalized alpha-Chloroalkyllithium: Synthesis of Cyclic Targets Related to Epibatidine

作者：Emerson Christopher R; Zakharov Lev N; Blakemore Paul R^*

来源：Organic Letters, 2011, 13(6): 1318-1321.

DOI：10.1021/ol103170y

Enantioenriched 1-chloro-2-(1,3-dioxolan-2-yl)ethyllithium was generated by PhLi initiated sulfoxide-ligand exchange and deployed in situ for sequential double stereospecific reagent-controlled homologation (StReCH) of B-(2-chloro-pyrid-5-yl) pinacol boronate. This process afforded highly functionalized contiguous stereodiad motifs (typically, % ee >= 98%, dr >= 85:15) amenable to subsequent annulative transformations as demonstrated by the concise synthesis (5-7 steps) of cyclic adducts related to the analgesic alkaloid epibatidine.

• 出版日期2011-3-18