γ- and δ-Hydroxynitriles: diastereoselective electrophile-dependent alkylations
作者:Robert J. Mycka、William T. Eckenhoff、Omar W. Steward、Nathan Z. Barefoot、Fraser F. Fleming
DOI:10.1016/j.tet.2012.10.016
日期:2013.1
allows highly diastereoselective alkylations controlled by the asymmetry of the remote carbinol stereocenter. Mechanistic experiments are consistent with γ-hydroxynitriles alkylating via a chelated magnesiated nitrile whereas δ-hydroxynitriles favor alkylation from acyclic magnesiated nitriles. Collectively these alkylations; are the first electrophile-dependentalkylations of acyclic nitriles, exhibit
作者:Robert J. Mycka、Omar W. Steward、Fraser F. Fleming
DOI:10.1021/ol101030r
日期:2010.7.2
centers are efficiently installed in chelation-controlled alkylations of acyclic hydroxynitriles. Intriguingly, the stereoselectivity is determined by the nature of the electrophile and the structure of the Grignard used for the deprotonation. The alkylation strategy addresses the long-standing difficulty of performing diastereoselective alkylations with conformationally mobile, acyclic nitriles.