Chiral ruthenium Lewis acid-catalyzed nitrile oxide cycloadditions
作者:Yasmin Brinkmann、Reniguntala J. Madhushaw、Rodolphe Jazzar、Gerald Bernardinelli、E. Peter Kündig
DOI:10.1016/j.tet.2007.06.033
日期:2007.8
(acetone)(R,R)-BIPHOP-F)Cp][SbF6], a transition metal Lewisacid that catalyzes the [3+2] dipolarcycloadditionreaction between aryl nitrile oxides and α,β-unsaturated aldehydes to give chiral 2-isoxazolines with yields of 43–98% and asymmetric purity of 60–93% ee. The stereochemistry of the major enantiomer is S, consistent with an approach of the nitrile oxide to the Cα-Si face of the enal in the anti-s-trans