title: Catalytic asymmetric insertion of diazoesters into aryl-CHO bonds: highly enantioselective construction of chiral all-carbon quaternary centers.
abstract: This paper describes a catalytic enantioselective route to synthesize functionalized all-carbon quaternary acyclic systems via a boron Lewis acid-promoted formal C-C insertion of diazoesters into aryl-CHO bonds. In the presence of chiral (S)-oxazaborolidinium cation 1d as a catalyst, the reaction proceeded in good yield (up to 83%) with good regioselectivity (up to 88:12) and excellent enantioselectivity (up to 99% ee). The synthetic potential of this method was illustrated by conversion of the products to both α- and β-amino esters.
authors.affiliation: Department of Chemistry, Sungkyunkwan University , Suwon, Gyeonggi-do 440-746, Korea.
authors.forename: Lizhu
authors.initials: L
authors.lastname: Gao
authors.forename: Byung Chul
authors.initials: BC
authors.lastname: Kang
authors.forename: Do Hyun
authors.initials: DH
authors.lastname: Ryu