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
Cobalt(III)-Catalyzed Dehydrative [4+2] Annulation of Oxime with Alkyne by CH and NOH Activation
作者:Malay Sen、Deepti Kalsi、Basker Sundararaju
DOI:10.1002/chem.201503643
日期:2015.10.26
Efficient, scalable cobalt‐catalyzed redox‐neutral [4+2] annulation of readily available oximes and alkyne is reported. The developed synthetic methodology is widely applicable and tolerates various functional groups including heterocycles. A stable Cp*CoIII neutral complex is employed as the catalyst for this redox‐neutral [4+2] annulation reaction, which progresses smoothly by way of a reversible
据报道,高效,可扩展的钴催化的氧化还原中性[4 + 2]环化易于获得的肟和炔烃。所开发的合成方法学广泛适用,并能耐受包括杂环在内的各种官能团。稳定的Cp * Co III中性络合物用作该氧化还原-中性[4 + 2]环化反应的催化剂,该反应通过可逆的环金属化反应顺利进行,而无需任何外部氧化剂,仅产生水作为副产物。
Rh-catalyzed sequential oxidative C–H activation/annulation with geminal-substituted vinyl acetates to access isoquinolines
作者:Haoke Chu、Song Sun、Jin-Tao Yu、Jiang Cheng
DOI:10.1039/c5cc04708k
日期:——
The concise synthesis of 3-substituted or non-C3-substituted isoquinolines through Rh-catalyzed sequential oxidativeC-Hactivation/annulation with geminal-substituted vinyl acetates was developed.