Synthesis of Isoquinoline Derivatives via Palladium‐Catalyzed C−H/C−N Bond Activation of
<i>N</i>
‐Acyl Hydrazones with
<i>α</i>
‐Substituted Vinyl Azides
A palladium‐catalyzed cyclization of N‐acetyl hydrazones with vinyl azides has been developed. Various substituted isoquinolines, including diverse fused isoquinolines can be prepared via this protocol in moderate to good yields. Mechanistic studies suggest that α‐substituted vinyl azide serves as an internal nitrogen source. Also, C−H bond activation and C−N bond cleavage have been realized using
a selective phosphoranation of alkynes with phosphoniumcation, which directs a concise approach to isoquinolines from unactivated alkyne and nitrile feedstocks in a single step. Mechanistic studies suggest that the annulation reaction is initiated by the unprecedented phosphoranation of alkynes, thus representing a unique reaction pattern of phosphonium salts and distinguishing it from existing protocols
Traceless heterocycle synthesis based on transition-metal-catalyzed C-H functionalization is synthetically appealing but has been realized only in monodentate directing systems. Bidentate directing systems allow for the achievement of high catalytic reactivity without the need for a high-cost privileged ligand. The first bidentate directing-enabled, traceless heterocycle synthesis is demonstrated in the
We show a beneficial new approach to the preparation of 1-methyl-3-phenylisoquinoline derivatives. This method involves heating polyphosphate ester and the appropriate oximes obtained from 3,4-diphenylbut-3-en-2-one derivatives. The isoquinolines were synthesised in yields mainly ranging from about 50 to 70%, and their structures were confirmed by proton and carbon nuclear magnetic resonance spectroscopy
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