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
A novel and general procedure for Cu-catalyzed coupling of enamides with alkynes to synthesize substituted pyridines was developed. The chemistry was allowed to extend to the synthesis of substituted isoquinolines by coupling of enamides with arynes under transition-metal-free conditions.
An efficient rhodium(III)-catalyzed C–H activation followed by intermolecular annulation between enamides and sulfoxonium ylides has been developed. The transformation proceeds smoothly with a broad range of substrates, affording a series of isoquinoline derivatives in moderate to good yields under additive-free conditions.
已经开发出一种高效的铑 ( III ) 催化的 C-H 活化,然后在烯酰胺和亚砜叶立德之间进行分子间成环。该转化可在多种底物中顺利进行,在无添加剂的条件下以中等至良好的产率提供一系列异喹啉衍生物。