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Full Paper
Chiral NCN Pincer Rhodium(III) Complexes with Bis(imidazolinyl)phenyl Ligands: Synthesis and Enantioselective Catalytic Alkynylation of Trifluoropyruvates with Terminal Alkynes
Article first published online: 28 FEB 2013
DOI: 10.1002/adsc.201200967
Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Additional Information
How to Cite
Wang, T., Niu, J.-L., Liu, S.-L., Huang, J.-J., Gong, J.-F. and Song, M.-P. (2013), Chiral NCN Pincer Rhodium(III) Complexes with Bis(imidazolinyl)phenyl Ligands: Synthesis and Enantioselective Catalytic Alkynylation of Trifluoropyruvates with Terminal Alkynes. Adv. Synth. Catal., 355: 927–937. doi: 10.1002/adsc.201200967
Publication History
- Issue published online: 25 MAR 2013
- Article first published online: 28 FEB 2013
- Manuscript Received: 12 NOV 2012
Funded by
- National Natural Science Foundation of China. Grant Number: Nos. 21072177 and 21272217
Keywords:
- asymmetric alkynylation;
- Phebim ligands;
- pincer rhodium(III) complexes;
- terminal alkynes;
- trifluoropyruvates
Abstract
A series of new chiral C2-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.