CuBr-Catalyzed Oxidative Difluoromethylation of Tertiary Amines with Difluoroenol Silyl Ethers

Abstract

CuBr-catalyzed oxidative difluoromethylation of readily available tertiary amines with difluoroenol silyl ethers was performed under mild conditions to afford beta-amine-alpha,alpha-difluoro ketones.

Synthesis of α,α-difluoro-β-amino carbonyl-containing sulfonamides and related compounds

“…For example, a,a-difluoro carbonyl compounds are known to form relatively stable hydrates, the feature that renders them inhibitors of wide range of the enzymatic cleavage of peptide bonds [8]. Consequently, synthesis of this type of compounds, in particular, b-amino-a,a-difluoro ketone or acid derivatives has received appropriate attention [9].…”

“…Despite progresses in this area [9], one interesting structural type of fluorinated sulfonamides of type 2 (Fig. 1), bearing pharmacophoric b-amino carbonyl moiety, is still hitherto unknown.…”

Beyond Traditional Cross Couplings: The Scope of the Cross Dehydrogenative Coupling Reaction

“…[23] The authors propose that the reaction mechanism is similar to that previously reported for the coupling of dialkylmalonates to isoquinolines, that is, the formation of a copper-imminium ion to which the nucleophilic difluoroenol silyl ether adds. Initially the reaction between isoquinolines and difluoroenol silyl ethers was investigated under the same conditions reported by Li and coworkers.…”

Organocatalytic asymmetric Michael reaction with acylsilane donors

“…We have tried to improve the catalytic result through introducing more hydrogen bond donors into chiral guanidine catalysts (3k, 3l). Unfortunately, the expected improvement of reaction result was not found (Table 1, entries [11][12]. The substitution of the trimethylsilyl group with a dimethylphenylsilyl group on the acylsilane gives a higher yield (81%) with slightly lower dr (16 : 1) and similar ee value (91%) ( Table 1, entry 13).…”

“…Since their discovery by Brook in 1957, 1-3 acylsilanes have been the one of the most powerful and efficient compounds that have the silicon directly attached to the carbonyl group, exhibiting particular physical and chemical properties, [4][5][6][7][8] so that they can be easily transformed into many different derivatives in one pot, such as acid, 9-12 ketone, [13][14][15] alcohol, 16,17 aldehyde, 11,18,19 cyanogen, 20 amide 12,20,21 and ester. 20,22 In addition to these radical reactions, a great deal of effort has been devoted to the development of various other kinds of acylsilane reactions, for instance, stereocontrolled nucleophilic additions, 23 stereocontrolled aldol reactions, 24 cyclization, 25 coupling reaction, 26 α-halogenations, 3 and enantioselective reduction.…”