Combining Hydrodefluorination and Defluorophosphorylation for Chemo- and Stereoselective Synthesis of gem-Fluorophosphine Alkenes

Abstract

General information, experimental procedures, optimization of reaction conditions, mechanistic studies, crystal data, and spectral data for all new compounds (PDF)Accession Codes CCDC 2224890 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk

Transition-Metal-Free Hydrodefluoroamination of Trifluoromethyl Enones for the Synthesis of α-Fluoroenamides

“…Based on mechanistic verification experiments and literature reports, − a plausible reaction mechanism is depicted in Scheme . Initially, the selective defluorinative multihydrogenation of β-CF 3 -enones with PhSiH 3 occurs through a sequence of carbonyl reduction (via OH-containing trifluoromethyl alkene A ) and downstream hydrodefluorination (via intermediate B ), leading to hydroxyl-containing gem -difluoroalkene C (pathway a).…”

“…Meanwhile, the remaining alkene 9 was recovered in 29% yield. The result revealed that the carbonyl group is essential for inhibiting competitive reactions, thus maintaining high reaction efficiency and chemoselectivity …”

“…We recently discovered that preinstalling a carbonyl substituent on alkenyl-CF 3 as an auxiliary unit offers an opportunity for selective and controllable C­(sp 3 )-F bond transformation . Generally, the single or two elusive C­(sp 3 )-F bonds become more amenable to displacement, thereby enabling the flexible skeletal modification of trifluoromethyl enones.…”

β-Trifluoromethylated enones as trifluoromethylated synthons in asymmetric catalysis

“…In this way, β-trifluoromethylated enones are also ingeniously subjected to defluorinations for the preparation of gem -difluorovinyl groups under electroreductive conditions. 10 According to this fascinating reactivity, numerous models of organo- or organometal-catalyzed reactions of β-trifluoromethylated enones are widely investigated in the literature. Although some reviews have been published on the application of β-trifluoromethylated enones, 8,9,11 few reviews are available about its asymmetric catalysis.…”