Palladium-catalyzed activation of E-E and C-E bonds in diaryl dichalcogenides (E = S, Se) under microwave irradiation conditions
作者:V. P. Ananikov、N. V. Orlov、I. P. Beletskaya
DOI:10.1007/s11172-005-0292-6
日期:2005.3
The firstexample of palladium-catalyzed stereoselective addition of diphenyl disulfide and diphenyl diselenide to the triple bond of terminal alkynes under microwave irradiation conditions is described. It was found that both the element—element (E-E) and carbon—element bonds can be activated in the catalytic system studied. The products of both reactions were isolated in quantitative yields. According
描述了在微波辐射条件下钯催化的二苯基二硫醚和二苯基二硒化物立体选择性加成到末端炔烃的三键的第一个例子。发现元素-元素(EE)和碳-元素键都可以在所研究的催化体系中被激活。两种反应的产物均以定量产率分离。根据量子化学计算,反应机制涉及 EE 键与 Pd0 的氧化加成。根据微波功率和反应条件,下一阶段是与炔烃的反应或碳元素键活化。Ph2Se2与Pd0氧化加成的产物,即双核络合物[Pd2(SePh)4(PPh32],
Palladium-catalyzed addition and carbonylative addition of diaryl disulfides and diselenides to terminal acetylenes
Novel transition-metal-catalyzed reactions of disulfides and diselenides with acetylenes are described. In the of tetrakis(triphenylphosphine)palladium(0), [Pd(PPh3)4], the (1) of diaryl disulfides and diselenides to terminal acetylenes 1 takes place stereoselectively to give high yields of (Z)-1,2-bis(arylthio)-1-alkenes 2 and (Z)-1,2-bis(arylseleno)-1-alkenes 3, respectively. A mechanistic proposal includes the following: (1) oxidative addition of (ArY)2 [Y = S, Se] to low-valent palladium species, (2) stereoselective cis-thiopalladation or cis-selenopalladation to acetylenes to form a cis-vinylpalladium intermediate, and (3) reductive elimination of the product with retention of the stereochemistry. When the reaction of diaryl disulfides and diselenides with terminal acetylenes is performed under the pressure of carbon monoxide, the carbonylative addition occurs to afford (Z)-1,3-bis(arylthio)-2-alken-1-ones 4 and (Z)-1,3-bis(arylseleno)-2-alken-1-ones 5, respectively. Carbon monoxide is regioselectively incorporated on the side of the terminal carbon of the acetylenes.
Solvent-free palladium-catalyzed addition of diaryl dichalcogenides to alkynes
作者:V. P. Ananikov、I. P. Beletskaya
DOI:10.1023/b:rucb.0000035637.57608.51
日期:2004.3
Solvent-free palladium-catalyzed addition of diaryl disulfides and diselenides to terminal alkynes makes it possible to achieve high stereoselectivity and almost 100% yields in approximate to10 min using only 0.1 mol.% catalyst. Both Pd(PPh3)(4) and easily available Pd(OAc)(2) and PdCl2 can be used in the reaction with an excess of triphenylphosphine. The catalyst and triphenylphosphine are readily recycled for repeated use. The study of the mechanism of the solvent-free catalytic reaction indicates that the process involves binuclear palladium complexes.