Chiral phosphorate anions are shown to be highly enantioselective templates for proton-transfer catalysis. A salt generated in situ from a bridgehead amine and a BINOL-derived chiral phosphoric acid serves as an effective proton-shuttle that exhibits remarkable enantioselectivity in a bioinspired, triple co-operative catalysis involving an achiral NHC. Thioesters with a β-chiral center can be prepared
Carbene-Catalyzed [4 + 2] Cycloadditions of Vinyl Enolate and (in Situ Generated) Imines for Enantioselective Synthesis of Quaternary α-Amino Phosphonates
作者:Jun Sun、Chengli Mou、Zhongyao Wang、Fangcheng He、Jian Wu、Yonggui Robin Chi
DOI:10.1021/acs.orglett.8b02707
日期:2018.9.21
A carbene-catalyzed enantioselectiveaddition of enals to five-membered cyclicimines is developed. The reaction gives chiral quaternary α-amino phosphonates bearing tetrasubstituted carbon centers with excellent enantioselectivities. The imine substrates can be generated in situ from the corresponding amines under an oxidative condition that is compatible with the carbene catalysis. Thus, a one-pot