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Title: (Guanidine) copper complex-catalyzed enantioselective dynamic kinetic allylic alkynylation under biphasic condition
Authors: Cui, Xi-Yang
Ge, Yicen
Tan, Siu Min
Jiang, Huan
Tan, Davin
Lu, Yunpeng
Lee, Richmond
Tan, Choon-Hong
Keywords: Science::Chemistry
Issue Date: 2018
Source: Cui, X.-Y., Ge, Y., Tan, S. M., Jiang, H., Tan, D., Lu, Y., . . . Tan, C.-H. (2018). (Guanidine) copper complex-catalyzed enantioselective dynamic kinetic allylic alkynylation under biphasic condition. Journal of The American Chemical Society, 140(27), 8448-8455. doi:10.1021/jacs.7b12806
Journal: Journal of the American Chemical Society
Abstract: Highly enantioselective allylic alkynylation of racemic bromides under biphasic condition is furnished in this report. This approach employs functionalized terminal alkynes as pro-nucleophiles and provides 6- and 7-membered cyclic 1,4-enynes with high yields and excellent enantioselectivities (up to 96% ee) under mild conditions. Enantioretentive derivatizations highlight the synthetic utility of this transformation. Cold-spray ionization mass spectrometry (CSI-MS) and X-ray crystallography were used to identify some catalytic intermediates, which include guanidinium cuprate ion pairs and a copper-alkynide complex. A linear correlation between the enantiopurity of the catalyst and reaction product indicates the presence of a copper complex bearing a single guanidine ligand at the enantio-determining step. Further experimental and computational studies supported that the alkynylation of allylic bromide underwent an anti-SN2' pathway catalyzed by nucleophilic cuprate species. Moreover, metal-assisted racemization of allylic bromide allowed the reaction to proceed in a dynamic kinetic fashion to afford the major enantiomer in high yield.
ISSN: 0002-7863
DOI: 10.1021/jacs.7b12806
Rights: This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of the American Chemical Society, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see
Fulltext Permission: open
Fulltext Availability: With Fulltext
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