Copper-Catalyzed Highly Enantioselective Difluoroalkylation of Secondary Propargyl Sulfonates with Difluoroenoxysilanes

Abstract

Transition-metal-catalyzed asymmetric fluoroalkylation remains a challenging topic due to the lack of efficient enantioselective catalysts to facilitate the catalytic cycle with fluoroalkylating reagents. In this article, Zhang and co-workers report a copper-catalyzed highly enantioselective difluoroalkylation of secondary propargyl sulfonates using difluoroenoxysilanes. The combination of copper with PyBox shows a highly catalytic effect for the enantioselective synthesis of propargylic a,a-difluoroketones that can serve as versatile building blocks for diverse transformations.

Regioselective Markovnikov hydrodifluoroalkylation of alkenes using difluoroenoxysilanes

“…Easily available difluoroenoxysilane 2 48 has been established as a versatile difluoro reagent 49 – 57 , to introduce an α,α-difluorinated ketone moiety that can undergo various diversifying reactions. However, its application in alkene hydrodifluoroalkylation remains unexplored.…”

Ruthenium‐Catalyzed Enantioselective Propargylic Phosphinylation of Propargylic Alcohols with Phosphine Oxides

“…Since the first discovery of ruthenium‐catalyzed enantioselective propargylic substitution reactions with acetone as a carbon‐centered nucleophile, [7] transition metal‐ and organo‐catalyzed enantioselective propargylic substitution reactions of propargylic alcohols or their derivatives have been reported by our and other research groups [8–10] . A variety of nucleophiles including carbon‐, [7, 9a–g, 10c,d] nitrogen‐, [9h–l] sulfur‐, [9m, 10c] oxygen‐, [9n–r] and hydrogen‐centered nucleophiles [10b,f] were applicable to achieve a high enantioselectivity, however, no successful example of enantioselective propargylic substitution reactions with phosphorus‐centered nucleophiles has appeared until now (Scheme 1 b). [11] Based on these research backgrounds and the significance to generate a carbon–phosphorus bond formation, we have envisaged enantioselective propargylic substitution reactions with phosphorus‐centered nucleophiles [12] .…”

Regioselective Markovnikov Hydrodifluoroalkylation of Difluoroenoxysilanes with Alkenes

“…近年来, 通过光氧化还原催化或外加氧化剂的方 法, 经过自由基历程已成功实现了烯烃的反马氏区域选 择性氢二氟烷基化反应合成直链型的加成产物(Scheme 1, a) [2] . 尽管该领域已取得了一定进展, 但这些方法仍 [3] 、施敏 [4] 、周剑 [5] 、马军安 [6] 、 张新刚 [7] 和彭勃 [8] 等课题组发展了系列二氟烯醇硅醚参 与的二氟烷基化反应. 基于对二氟烯醇硅醚性质的认 识, 华东师范大学化学与分子工程学院周剑和余金生等 考虑是否能利用酸活化烯烃产生碳正离子中间体, 并使…”