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Lewis Base Assisted Brønsted Base Catalysis: Direct Regioselective Asymmetric Vinylogous Alkylation of Allylic Sulfones
Author(s) -
Jiang Lin,
Lei Qian,
Huang Xin,
Cui HaiLei,
Zhou Xue,
Chen YingChun
Publication year - 2011
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.201100534
Subject(s) - regioselectivity , tsuji–trost reaction , cinchona , chemistry , nucleophile , alkylation , lewis acids and bases , catalysis , enantiomer , organic chemistry , brønsted–lowry acid–base theory , dimethyl carbonate , medicinal chemistry , organocatalysis , enantiomeric excess , allylic rearrangement , enantioselective synthesis
A Lewis base assisted Brønsted base catalysis (LBABB) strategy is applied for direct asymmetric vinylogous alkylation of allylic sulfones with Morita–Baylis–Hillman (MBH) carbonates, in which a strong Brønsted base, tert ‐butoxy anion, generated in situ from a tertiary amine catalyst and MBH carbonate, is crucial in activating unstabilized nucleophiles. The γ‐regioselective alkylation products were obtained with good to excellent enantiomeric excess values when catalyzed by a modified cinchona alkaloid.