title: Enantioselective Synthesis of syn-α-Aryl-β-hydroxy Weinreb Amides: Catalytic Asymmetric Roskamp Reaction of α-Aryl Diazo Weinreb Amides.
abstract: A convenient one-pot procedure to synthesize a variety of highly optically active syn-α-aryl-β-hydroxy Weinreb amides using an asymmetric Roskamp/reduction strategy is described. An oxazaborolidinium ion catalyzed asymmetric Roskamp reaction of α-aryl diazo Weinreb amides with aldehydes produced α-phenyl-β-keto Weinreb amides, which were in situ reduced with zinc borohydride to give syn-α-aryl-β-hydroxy Weinreb amides in good yields (up to 87%) with high enantioselectivities (up to 99% ee) and syn stereoselectivities (>20:1).
authors.affiliation: Department of Chemistry, Sungkyunkwan University , Suwon 440-746, Korea.
authors.forename: Sung Ho
authors.initials: SH
authors.lastname: Shin
authors.affiliation: Department of Chemistry, Sungkyunkwan University , Suwon 440-746, Korea.
authors.forename: Eun Hee
authors.initials: EH
authors.lastname: Baek
authors.affiliation: Western Seoul Center, Korea Basic Science Institute , Seoul 120-140, Korea.
authors.forename: Geum-Sook
authors.initials: GS
authors.lastname: Hwang
authors.affiliation: Department of Chemistry, Sungkyunkwan University , Suwon 440-746, Korea.
authors.forename: Do Hyun
authors.initials: DH
authors.lastname: Ryu