Enantioselective dearomative [3+2] annulation of 5-amino-isoxazoles with quinone monoimines

Chem Commun (Camb). 2020 Nov 14;56(88):13591-13594. doi: 10.1039/d0cc05807f. Epub 2020 Oct 15.

Abstract

The first enantioselective dearomative [3+2] annulation of 5-amino-isoxazoles with quinone monoimines was realized using a chiral phosphoric acid as catalyst. Various novel (bridged) isoxazoline fused dihydrobenzofurans bearing two continuous quaternary stereocenters were achieved in moderate to good yields (up to 94%) with moderate to good enantioselectivities (up to 98% ee). The absolute configurations of two products were assigned by X-ray crystal structural analyses and a plausible reaction mechanism was proposed.