N-hydroxypyridine-2(1H)-thione derivatives of carboxylic acids as activated esters. Part I. The synthesis of carboxamides
作者:Derek H.R. Barton、J. Albert Ferreira
DOI:10.1016/0040-4020(96)00487-5
日期:1996.7
The reaction between an acyl derivative of N-hydroxypyridine-2(1H)-thione (a Barton PTOC ester) and either an amine (primary or secondary), or the corresponding sulfenamide, led to the formation of a carboxamide in a clean transformation requiring minimal work-up and purification. The reaction with a sulfenamide is particularly useful since the only by-product, an unsymmetrical disulfide, is of both
N-hydroxypyridine-2(1H)-thione derivatives of carboxylic acids as activated esters. Part II. Applications in peptide synthesis
作者:Derek H.R. Barton、J. Albert Ferreira
DOI:10.1016/0040-4020(96)00488-7
日期:1996.7
The N-hydroxypyridine-2(1H)-thione derivatives of two urethane-protected α-amino acids readily reacted with free α-amino acid esters or the corresponding benzenesulfenamides to give simple dipeptides in reasonable yields. The benzenesulfenamides are the reagents of choice since they allowed for neutral reaction conditions and exhibited superior reactivity in sterically demanding instances. The atom-economical
New Reactions of the Thiocarbonyl Function. The Synthesis of Hindered Peptides
作者:Derek H. R. Barton、J. Albert Ferreira
DOI:10.1080/10426509708545507
日期:1997.1.1
chemistry of the thiocarbonyl function has been expanded to include the concerted reaction between an O-acyl derivative of N-hydroxypyridine-2(1H)-thione (a Barton PTOC ester) and a sulfenamide. The atom-economical process spawned a carboxamide and an unsymmetrical disulfide of synthetic and biological value. The reaction was successfully applied to the synthesis of sterically encumbered, urethane-protected
Regio- and stereoselective thiocarbamoylation of terminal alkynes Successfully took place Using 2,4,5-tri-Cl-C6H2SNEt2 as a reaction substrate and PdCl2(PPh3)(2)/PPh3/n-Bu4NCl as a catalyst system. (c) 2005 Elsevier Ltd. All rights reserved.
Palladium-Catalyzed Azathiolation of Carbon Monoxide
A novel palladium-catalyzed azathiolation of carbon monoxide using sulfenamide (RSNR'(2)) (1) is described to provide thiocarbamate 2 in good yields. The mechanistic proposal includes the following: (1) insertion of CO into Pd-S bond of Pd(SR)(2)(PPh3)(n) 4 to provide Pd[C(O)SR](SR)-(PPh3)(n) 5 and (2) sigma-bond metathesis between S-N and Pd-C(O) bonds to afford 2 with the regeneration of 4.