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Chiral NCN Pincer Rhodium(III) Complexes with Bis(imidazolinyl)phenyl Ligands: Synthesis and Enantioselective Catalytic Alkynylation of Trifluoropyruvates with Terminal Alkynes
Author(s) -
Wang Tao,
Niu JunLong,
Liu ShuangLiang,
Huang JuanJuan,
Gong JunFang,
Song MaoPing
Publication year - 2013
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201200967
Subject(s) - chemistry , alkynylation , rhodium , enantioselective synthesis , trifluoromethyl , catalysis , pincer movement , medicinal chemistry , organic chemistry , combinatorial chemistry , alkyl
A series of new chiral C 2 ‐symmetrical NCN pincer rhodium(III) complexes with bis(imidazolinyl)phenyl ligands have been conveniently synthesized from easily available materials. The complexes were subsequently applied in the enantioselective addition of terminal alkynes to trifluoropyruvates. With catalyst loading of 1.5–3.0 mol%, the alkynylation of ethyl or methyl trifluoropyruvate with a variety of electronically and structurally diverse terminal alkynes gave the optically active trifluoromethyl‐substituted tertiary propargylic alcohols with enantioselectivities of up to >99% ee and high yields. Although good to excellent enantioselectivities (85–98% ee ) could be achieved only for some of the aliphatic terminal alkynes under the optimized conditions, the enantioselectivities were consistently excellent (94% to >99% ee ) in the case of aromatic as well as heteroaromatic alkynes and enynes.