5-Substituted Derivatives of the Tricyclic (+)-Sparteine Surrogate in the Enantioselective Lithiation/Stannylation of an<i>O</i>-Alkyl Carbamate
作者:Matthias Breuning、David Hein
DOI:10.1002/ejoc.201300987
日期:2013.11
5-Mono- and 5,5-disubstituted tricyclic bispidines, derivatives of the known (+)-sparteinesurrogate, have been synthesized in four-to-six steps from the natural alkaloid (–)-cytisine and evaluated as chiral ligands in the enantioselectivelithiation/stannylation of an O-alkyl carbamate. Structure–selectivity studies revealed that a small 5-endo substituent is tolerated, whereas larger 5-endo substituents