Access to Aryl and Heteroaryl Trifluoromethyl Ketones from Aryl Bromides and Fluorosulfates with Stoichiometric CO
作者:Martin B. Johansen、Oliver R. Gedde、Thea S. Mayer、Troels Skrydstrup
DOI:10.1021/acs.orglett.0c01117
日期:2020.6.5
trifluoromethyl ketones starting from readily accessible aryl bromides and fluorosulfates, the latter easily prepared from the corresponding phenols. The methodology utilizes low pressure carbon monoxide generated ex situ from COgen to generate Weinreb amides as reactive intermediates that undergo monotrifluoromethylation affording the corresponding aromatic trifluoromethyl ketones (TFMKs) in good
remains a challenging topic. Here, we report a copper-catalyzed highly enantioselectivedifluoroalkylation of secondary propargyl sulfonates using difluoroenoxysilanes. The reaction proceeds under mild reaction conditions with Cu(I)/PyBox as the catalyst. The advantages of this method include high efficiency, high enantioselectivity (enantiomeric ratio up to 99:1), and excellent functional-group tolerance
The trifluoromethylation of iodoarenes was accomplished by use of a 2-trifluoromethylbenzimidazoline derivative as the trifluoromethylating reagent and a catalytic amount of Cu(I) in the presence of 2,2'-bipyridyl as the ligand. Through a mechanistic study, we found that the oxidative addition of the iodoarene to the Cu(I)–CF3 species is the rate-determining step.
Phosphine-Catalyzed Direct δ-Carbon Addition of Alkynones to Electron-Deficient Carbonyl-Group-Containing Compounds: Preparation of Conjugated Dienes
作者:Yao-Liang Sun、Xiao-Nan Zhang、Yin Wei、Min Shi
DOI:10.1002/cctc.201600811
日期:2016.10.6
reaction site and trapped by electron‐deficient carbonyl‐group‐containing compounds upon phosphine catalysis, which provided three kinds of δ‐addition and isomerization products in moderate to excellent yields. Plausible mechanisms were proposed on the basis of deuterium‐labeling experiments. Thus, a novel strategy for phosphine‐catalyzed δ‐carbon addition of alkynones to electron‐deficient carbonyl groups
A Carbene Strategy for Progressive (Deutero)Hydrodefluorination of Fluoroalkyl Ketones
作者:Xiaolong Zhang、Xinyu Zhang、Qingmin Song、Paramasivam Sivaguru、Zikun Wang、Giuseppe Zanoni、Xihe Bi
DOI:10.1002/anie.202116190
日期:2022.2.7
A carbene strategy for the sequential (deutero)hydrodefluorination of fluoroalkyl ketones is reported. This method allowed for the controllable preparation of difluoroalkyl- and monofluoroalkyl ketones from aryl- and alkyl-substituted perfluoroalkyl ketones in high yield with excellent functional group tolerance.