title: Pentanidium-catalyzed enantioselective phase-transfer conjugate addition reactions.
abstract: A new chiral entity, pentanidium, has been shown to be an excellent chiral phase-transfer catalyst. The enantioselective Michael addition reactions of tert-butyl glycinate-benzophenone Schiff base with various α,β-unsaturated acceptors provide adducts with high enantioselectivities. A successful gram-scale experiment at a low catalyst loading of 0.05 mol % indicates the potential for practical applications of this methodology. Phosphoglycine ester analogues can also be utilized as the Michael donor, affording enantioenriched α-aminophosphonic acid derivatives and phosphonic analogues of (S)-proline.
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543.
authors.forename: Ting
authors.initials: T
authors.lastname: Ma
authors.forename: Xiao
authors.initials: X
authors.lastname: Fu
authors.forename: Choon Wee
authors.initials: CW
authors.lastname: Kee
authors.forename: Lili
authors.initials: L
authors.lastname: Zong
authors.forename: Yuanhang
authors.initials: Y
authors.lastname: Pan
authors.forename: Kuo-Wei
authors.initials: KW
authors.lastname: Huang
authors.forename: Choon-Hong
authors.initials: CH
authors.lastname: Tan