title: Highly enantioselective organocatalytic Biginelli reaction.
abstract: A series of binol- and H8-binol-based phosphoric acids have for the first time been evaluated for their ability to catalyze Biginelli reactions of aldehydes, thiourea or urea, and beta-keto esters. A new chiral phosphoric acid, derived from 3,3'-diphenyl-H8-binol, exhibited superior catalytic activity and enantioselectivity compared to its structural analogues, affording high enantioselectivities ranging from 85 to 97% ee with a wide scope of substrates. A metal-free preparation of optically active monastrol was achieved on the basis of the current process.
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Xiao-Hua
authors.initials: XH
authors.lastname: Chen
authors.forename: Xiao-Ying
authors.initials: XY
authors.lastname: Xu
authors.forename: Hua
authors.initials: H
authors.lastname: Liu
authors.forename: Lin-Feng
authors.initials: LF
authors.lastname: Cun
authors.forename: Liu-Zhu
authors.initials: LZ
authors.lastname: Gong