Esterification of Thioamides via Selective N–C(S) Cleavage under Mild Conditions

Abstract

Herein, we report an exceedingly mild method for the direct, transition-metal-free esterification of thioamides through the selective generation of tetrahedral intermediates. The method represents the first transition-metal-free approach to the thioamide to thionoester transformation in organic synthesis. This reactivity has been accomplished through N,N-Boc 2 -thioamides that engage in ground-state destabilization of the n N → π* C�S conjugation. The ground-state destabilization of "single-atom" bioisosteric thioamides will expand the arsenal of valuable amide bond functionalization reactions.

Iodine-Catalyzed [5 + 1] Carbonylation of 2-Alkenyl/Pyrrolylanilines with CS2 as the Carbonylating Reagent

“…DMSO is activated by hydriodic acid to generate the sulfenium ion D . Subsequently, the elimination of iodine (I 2 ) and DMS (dimethyl sulfide) gives rise to intermediate F , which further undergoes elimination of 1/8 S 8 to produce 3a . The byproduct DMS (dimethyl sulfide) and S 8 can be detected by gas chromatography (refer to the Supporting Information).…”

Catalyst-free activation of N–C(O) Amide bonds – efficient cascade synthesis of N-acyl thiocarbamides in batch and continuous-flow

“…[6][7][8][9] Among amide bond activation strategies, the potential use of electronically dynamic or structurally twisted amides as acylating agents through N-C bond cleavage has undergone numerous transformations under transition-metal and metal-free conditions. [10][11][12][13][14][15][16] Over the last decade, amides have been crucial as donors for acyl or alkyl groups. [17][18][19] A multitude of acyl sub-stitution reactions involving amides have been developed, facilitating the synthesis of amides, 20 esters, 16,21,22 and ketones.…”

“…[10][11][12][13][14][15][16] Over the last decade, amides have been crucial as donors for acyl or alkyl groups. [17][18][19] A multitude of acyl sub-stitution reactions involving amides have been developed, facilitating the synthesis of amides, 20 esters, 16,21,22 and ketones. 10,18,23 Notably, transition-metal-free processes have been increasingly recognized within various reaction classes.…”