[reaction: see text] PEG has been used as a solvent medium for regioselective Heck reactions with easy recyclability of solvent and Pd catalyst for the first time.
Dioxygen-Promoted Regioselective Oxidative Heck Arylations of Electron-Rich Olefins with Arylboronic Acids
作者:Murugaiah M. S. Andappan、Peter Nilsson、Henrik von Schenck、Mats Larhed
DOI:10.1021/jo049434t
日期:2004.8.1
with arylboronicacids. This appears to constitute the first example of palladium(II)-catalyzed internal Heck arylations. The novel protocol exploits oxygen gas for environmentally benign reoxidation and a stable 1,10-phenanthroline bidentate ligand to promote the palladium(II) regeneration and to control the regioselectivity. Internal arylation is strongly favored with electron-rich arylboronic acids
Ligand-Free Reusable Palladium-Catalyzed Heck-Type Coupling Reactions of Hypervalent Iodine Reagents under Mild Conditions
作者:Xiaoming Qu、Peng Sun、Tingyi Li、Jincheng Mao
DOI:10.1002/adsc.201100008
日期:2011.5.9
Highly effective palladium‐catalyzed Heck‐type couplings of hypervalentiodinereagents are reported for the first time. It is noteworthy that such reactions could be carried out in the absence of ligand at 40 °C and the catalytic system could be easily reused for five times.
Functionalization of Alkynes Catalyzed byt-Bu-P4 Base
作者:Tatsushi Imahori、Chieko Hori、Yoshinori Kondo
DOI:10.1002/adsc.200404076
日期:2004.8
The addition of O- and N-nucleophiles to alkynescatalyzed by a phosphazene base, t-Bu-P4 base, was investigated. Alkynes were easily transformed to enol ethers and enamines in DMSO by the addition of nucleophiles. When phenylacetylene was reacted with diisopropylamine, a unique head-to-head dimerization of phenylacetylene was observed to give the enyne derivative. Terminal proton of phenylacetylene
Selective Terminal Heck Arylation of Vinyl Ethers with Aryl Chlorides: A Combined Experimental−Computational Approach Including Synthesis of Betaxolol
作者:Gopal K. Datta、Henrik von Schenck、Anders Hallberg、Mats Larhed
DOI:10.1021/jo0602367
日期:2006.5.1
medium. The selectivity for linear β-product in PEG-200 is slightly higher than in aqueous DMF. DFT calculations support a ligand-driven selectivity rationale, where the electronic and steric influence of bulky P(t-Bu)3 ligand provides improved β-selectivity in the essential insertion step also with electron-rich aryl chlorides. A tentative computational rationalization of the improved selectivity in non-methylated