Chiral NCN Pincer Rhodium(III) Complexes with Bis(imidazolinyl)phenyl Ligands: Synthesis and Enantioselective Catalytic Alkynylation of Trifluoropyruvates with Terminal Alkynes
作者:Tao Wang、Jun-Long Niu、Shuang-Liang Liu、Juan-Juan Huang、Jun-Fang Gong、Mao-Ping Song
DOI:10.1002/adsc.201200967
日期:2013.3.25
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
Modulation of the coordination geometries of NCN and NCNC Rh complexes for ambidextrous chiral catalysts
作者:Jun-ichi Ito、Takahiro Ishihara、Takaki Fukuoka、Siti Rokiah Binti Mat Napi、Hajime Kameo、Hisao Nishiyama
DOI:10.1039/c9cc06520b
日期:——
A chirality switch between novel NCN pincer Rh complexes and a related double cyclometalated NCNC Rh complex containing secondary amino groups is described. Their catalytic abilities were determined in asymmetric alkynylation of ethyltrifluoropyruvate, and the change in the coordination geometry of the Rh catalysts affected the stereochemistry of the products.
Thinking outside the box: A newly developed C1‐symmetric Rh/Phebox complex efficiently catalyzed the asymmetricalkynylation of α‐ketoester 1 with various aryl and alkyl substituted terminal alkynes to provide the corresponding chiral tertiary propargylic alcohols with up to 99 % ee (see scheme; TMS=trimethylsilyl).
A novel ruthenium catalyst is introduced which contains solely achiral ligands and acquires its chirality entirely from octahedral centrochirality. The configurationally stable catalyst is demonstrated to catalyze the alkynylation of trifluoromethyl ketones with very high enantioselectivity (up to >99% ee) at low catalyst loadings (down to 0.2 mol%).
Highly Enantioselective Alkynylation of Trifluoropyruvate with Alkynylsilanes Catalyzed by the BINAP−Pd Complex: Access to α-Trifluoromethyl-Substituted Tertiary Alcohols
作者:Kohsuke Aikawa、Yu̅ta Hioki、Koichi Mikami
DOI:10.1021/ol102541s
日期:2010.12.17
A highlyenantioselective alkynylation catalyzed by the dicationic (S)-BINAP−Pd complex with a variety of alkynylsilanes and trifluoropyruvate is described. The catalytic reaction is applicable to highlyenantioselective addition of polyyne to trifluoropyruvate to construct α-trifluoromethyl-substituted tertiaryalcohols as enantiomerically enriched forms. The alkynyl products can be converted into