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Highly Enantioselective Synthesis of β‐Heteroaryl‐Substituted Dihydrochalcones Through Friedel–Crafts Alkylation of Indoles and Pyrrole
Author(s) -
Wang Wentao,
Liu Xiaohua,
Cao Weidi,
Wang Jun,
Lin Lili,
Feng Xiaoming
Publication year - 2010
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.200902355
Subject(s) - enantioselective synthesis , pyrrole , friedel–crafts reaction , alkylation , catalysis , indole test , chemistry , chalcone , enantiomeric excess , enantiomer , asymmetric induction , organic chemistry , medicinal chemistry
Abstract A highly enantioselective Friedel–Crafts (F–C) alkylation of indoles and pyrrole with chalcone derivatives catalyzed by a chiral N,N′ ‐dioxide–Sc(OTf) 3 complex has been developed that tolerates a wide range of substrates. The reaction proceeds in moderate to excellent yields and high enantioselectivities (85–92 % enantiomeric excess) using 2 mol % (for indole) or 0.5 mol % (for pyrrole) catalyst loading, which showed the potential value of the catalyst system. Meanwhile, a strong positive nonlinear effect was observed. On the basis of the experimental results and previous reports, a possible working model is proposed to explain the origin of the activation and asymmetric induction.