Br, I, OAc, OTf) complexes, providing tertiary propargylic trifluoromethyl alcohols in high yields and with excellent chemoselectivity from a broad range of aryl‐ and more challenging alkyl‐substituted trifluoromethyl ketones (TFMKs). DFT calculations were performed to rationalize the correlation between the yield of catalytic alkynylation and the sterics of N‐heterocycliccarbenes (NHCs), expressed
Catalytic Enantioselective Alkynylation of Trifluoromethyl Ketones: Pronounced Metal Fluoride Effects and Implications of Zinc-to-Titanium Transmetallation
作者:Guang-Wu Zhang、Wei Meng、Hai Ma、Jing Nie、Wen-Qin Zhang、Jun-An Ma
DOI:10.1002/anie.201007341
日期:2011.4.4
(L1 and L2), was developed for the synthesis of both enantiomers of trifluoromethylated propargylic tertiary alcohols in high yield and enantioselectivity. Small amounts of BaF2 were found to be essential for maintaining high levels of reactivity and enantioselectivity.
new chiral CCN Rh catalysts containing N‐heterocyclic carbene and oxazoline hybrid ligands is described. The catalytic reaction of fluoroalkyl‐substituted ketones, ArCOCF2X (X=F, Cl, H), with aromatic and aliphatic alkynes yielded the corresponding chiral propargyl alcohols with high enantioselectivity. Control and kinetic experiments suggested a bis(alkynyl) Rh intermediate as the active species for
Enantioselective alkynylation of trifluoromethyl ketones catalyzed by chiral Schiff bases in the presence of Me2Zn afforded the corresponding trifluoroalkynyl alcohols in up to 66 % ee.
Enantioselective Alkynylation of Trifluoromethyl Ketones Catalyzed by Cation‐Binding Salen Nickel Complexes
作者:Dongseong Park、Carina I. Jette、Jiyun Kim、Woo‐Ok Jung、Yongmin Lee、Jongwoo Park、Seungyoon Kang、Min Su Han、Brian M. Stoltz、Sukwon Hong
DOI:10.1002/anie.201913057
日期:2020.1.7
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