Silver-catalysed/microwave-assisted domino reactions of 2-alkynyl-acetophenones and 3-acetyl-2-alkynylpyridines in the presence of ammonia are widely described. In most cases the reaction give a mixture of the imino- and carbo-cyclisation products, with a general preference for the former. A plausible mechanism is proposed and the dual activity of silver salts is supported by NMR experiments.
Palladium-Catalyzed CH Oxidation of Isoquinoline N-Oxides: Selective Alkylation with Dialkyl Sulfoxides and Halogenation with Dihalo sulfoxides
作者:Bo Yao、Ren-Jie Song、Yan Liu、Ye-Xiang Xie、Jin-Heng Li、Meng-Ke Wang、Ri-Yuan Tang、Xing-Guo Zhang、Chen-Liang Deng
DOI:10.1002/adsc.201101009
日期:2012.7.9
palladium‐catalyzed CHoxidation of isoquinoline N‐oxides has been developed for regioselectively synthesizing substituted isoquinolines. The method represents the first example of using dialkylsulfoxides as the alkyl sources for the construction of 1‐alkylated isoquinolines. Moreover, the regioselective halogenation of isoquinoline N‐oxides is also successful using dihalosulfoxides as the halide sources
A copper(I)-catalyzed tandemreaction of 2-bromoaryl ketones, terminal alkynes, and CH3CN is developed, which combines N atom transfer and three-component [3 + 2 + 1] cyclization, and efficiently produces densely functionalized isoquinolines in a facile, highlyselective, and general manner. In the reaction, the formation of aromatic C–N bonds along with the complete C–N triple bond cleavage is first
In this account, we summarize the peculiar effects and advantages of gold, silver, and titanium dual role catalysis over the uncatalyzed tandem imination/annulation processes of gamma- and delta-ketoalkynes. (C) 2010 Elsevier B.V. All rights reserved.