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Catalytic, Asymmetric Aza‐Baylis–Hillman Reaction of N ‐Sulfonated Imines with Activated Olefins by Quinidine‐Derived Chiral Amines
Author(s) -
Shi Min,
Xu YongMei,
Shi YongLing
Publication year - 2005
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200400872
Subject(s) - methyl vinyl ketone , methyl acrylate , chemistry , bifunctional , acrylate , adduct , lewis acids and bases , cinchona , catalysis , ketone , polymer chemistry , addition reaction , organic chemistry , medicinal chemistry , enantioselective synthesis , copolymer , polymer
The chiral nitrogen Lewis base, tricyclic cinchona alkaloid derivative TQO, is an effective promoter in the catalytic, asymmetric aza‐Baylis–Hillman reaction of N ‐sulfonated imines ArCHNR′ 1 (R′ = Ts, Ms, Ns, SES) with various activated olefins such as methyl vinyl ketone (MVK), ethyl vinyl ketone (EVK), acrolein, methyl acrylate, phenyl acrylate, or α‐naphthyl acrylate to give the corresponding adducts in moderate to good yields with good to high ee (up to 99 %) at −30 °C or 45 °C in various solvents, including DMF/MeCN (1:1, v/v). The first such reaction of 1 with the simplest Michael acceptor MVK and methyl acrylate has been achieved with excellent enantioselectivity. The adducts derived from MVK and EVK had the opposite absolute configuration to those from acrolein, methyl acrylate, phenyl acrylate, and α‐naphthyl acrylate. A plausible mechanism has been proposed on the basis of previous reports and the authors’ investigations. An effective bifunctional chiral nitrogen Lewis base–Brønsted acid system has been revealed in this type of aza‐Baylis–Hillman reaction.