Bifunctional Phosphine-Catalyzed Domino Reaction: Highly Stereoselective Synthesis of cis-2,3-Dihydrobenzofurans from Salicyl N-Thiophosphinyl Imines and Allenes

• DOI: 10.1021/ol802453c
• Publication Date: 2008-12-01T19:52:55Z
• Authors: Xiangtai Meng; You Huang; Ruyu Chen
• Keywords: Umpolung; Domino; Cascade reaction; Reactivity; Stereocenter

A new bifunctional phosphine catalyst, (2'-hydroxy-biphenyl-2-yl)-diethylphosphane (LBBA-1), was developed for the highly stereoselective synthesis of cis-2,3-dihydrobenzofurans via an aza-Morita-Baylis-Hillman/umpolung addition domino reaction salicyl N-thiophosphinyl imines with electron-deficient allenes. Dual activation both nucleophile and electrophile by catalyst accounts observed high reactivity stereoselectivity.