A synthesis of a novel electrophilic reagent 1,1,1-trifluoro-4-(phenylsulfonyl)-but-3-ene-2,2-diol 2 is described. The reaction of 2 with various electron-rich heteroaromatics such as furans, pyrroles, indoles is investigated. The addition-elimination reaction proceeds under mild conditions stereospecifically and permits a novel one-step procedure for the preparation of trifluoroacetylvinyl substituted heterocycles in high yield. In all cases only E-isomers of unsaturated CF3 ketones were obtained.
本文介绍了一种新型亲电试剂 1,1,1-三氟-4-(苯磺酰基)-丁-3-烯-2,2-二醇 2 的合成。研究了 2 与各种富电子杂芳烃(如呋喃、吡咯、吲哚)的反应。加成-消除反应在温和的条件下立体定向地进行,并允许采用一种新颖的一步法高产率制备三氟乙酰乙烯基取代的杂环。在所有情况下,只得到了不饱和 CF3 酮的 E 异构体。
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