Perfluoro-tagged, phosphine-free palladium nanoparticles supported on silica gel: application to alkynylation of aryl halides, Suzuki–Miyaura cross-coupling, and Heck reactions under aerobic conditions
cross-coupling, as well as in the Heck reaction between methyl acrylate and aryl iodides is described. The reactions are carried out under aerobic and phosphine-free conditions with excellent to quantitative product yields in each case. The catalysts are easily recovered and reused several times without significant loss of activity. The alkynylation of aryl halides (under copper-free conditions) and the Suzuki–Miyaura
Dibrominated addition and substitution of alkenes catalyzed by Mn<sub>2</sub>(CO)<sub>10</sub>
作者:Xianheng Song、Shanshui Meng、Hong Zhang、Yi Jiang、Albert S. C. Chan、Yong Zou
DOI:10.1039/d1cc04534b
日期:——
A practical method for the dibromination of alkenes without using molecular bromine is consistently appealing in organic synthesis. Herein, we report Mn-catalyzed dibrominated addition and substitution of alkenes only with N-bromosuccinimide, producing a variety of synthetically valuable dibrominated compounds in moderate to high yields.
An effective protocol was developed for the Heck coupling reactions between various aryl halides and olefins. In the presence of 2 mol% of Pd(OAc) 2 , the desired products could be obtained in good yields under ligand-free and aerobic conditions. The catalytic system could be easily recycled for five times with high efficiency.
作者:Guanlei Xie、Prinessa Chellan、Jincheng Mao、Kelly Chibale、Gregory S. Smith
DOI:10.1002/adsc.201000218
日期:——
thiosemicarbazone salicylaldiminato‐palladium(II) complexes of the general formula [Pd(saltsc‐R)PPh3] [saltsc=salicylaldehyde thiosemicarbazone; R=H (1), 3‐tert‐butyl (2), 3‐methoxy (3), 5‐chloro (4)], have been evaluated as catalyst precursors for the Mizoroki–Heck coupling reaction between a variety of electron‐rich and electron‐poor aryl halides and olefins. The palladium complexes (0.1–1 mol% loading) were found
The Heck reaction of cinnamyl alcohols with aryl iodides has been investigated using n-Bu4NOAc as the base in toluene. Under these conditions, the reaction affords regio- and stereoselectively (Z)-2,3-diarylallylic alcohols in moderate to good yields. Experimental evidence suggests that the observed selectivity in formation of the vinylic substitution products is kinetic in origin under these conditions and that both the base and the solvent play a key role.