Enantioselective Alkynylation of Trifluoromethyl Ketones Catalyzed by Cation-Binding Salen Nickel Complexes.

Dongseong Park, Carina I Jette, Jiyun Kim, Woo-Ok Jung, Yongmin Lee, Jongwoo Park, Seungyoon Kang, Min Su Han, Brian M Stoltz, Sukwon Hong

Angewandte Chemie (International ed. in English) 2020 Jan 07

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Cation-binding salen nickel catalysts were developed for the enantioselective alkynylation of trifluoromethyl ketones in high yield (up to 99 %) and high enantioselectivity (up to 97 % ee). The reaction proceeds with substoichiometric quantities of base (10-20 mol % KOt-Bu) and open to air. In the case of trifluoromethyl vinyl ketones, excellent chemo-selectivity was observed, generating 1,2-addition products exclusively over 1,4-addition products. UV-vis analysis revealed the pendant oligo-ether group of the catalyst strongly binds to the potassium cation (K+ ) with 1:1 binding stoichiometry (Ka =6.6×105 m-1 ). © 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Citation

Dongseong Park, Carina I Jette, Jiyun Kim, Woo-Ok Jung, Yongmin Lee, Jongwoo Park, Seungyoon Kang, Min Su Han, Brian M Stoltz, Sukwon Hong. Enantioselective Alkynylation of Trifluoromethyl Ketones Catalyzed by Cation-Binding Salen Nickel Complexes. Angewandte Chemie (International ed. in English). 2020 Jan 07;59(2):775-779