One-Pot Construction of ?-Selective Quinolines with ?-Quaternary Carbon from Vinylquinolines with Active Ylides via Pd/Sc/Br?nsted Acid Co-Catalysis

作者：Song, Longlong; Xiong, Lulu; Ni, Dan; Chen, Weixiong; Ji, Jian; Xue, Jian; Chen, Xuwen; Wu, Xiang; He, Xiao^*; Liu, Shunying^*

来源：ACS Catalysis, 2023.

DOI：10.1021/acscatal.2c05824

• Pd
• Sc co-catalysis
• one-pot reaction
• vinylquinolines
• active ylide
• quaternary carbon

Vinyl-substituted N-heterocycles, as more challenging inert olefins with more stable reactivity, have brought about widespread attention in the reaction of aza-Michael addition or reduction coupling reaction. Here, we report a [Pd(eta 3-C3H5)Cl]2/ Sc(OTf)3-catalyzed catalytic process accelerated by Bri nsted acids with a fi-selective aza-Michael addition to yield a gamma-quaternary carbon from vinyl-substituted quinolines, diazos, and anilines/ alcohols in one pot. The generation of anhydride analogues from Bri nsted acid and the counter anion (OTf-) of Lewis acid promotes the activation of the corresponding Lewis acid and the nearly quantitative transformation. Both pi-cation and coordination interactions play pivotal roles in the activation of the vinylquinoline substrates by the activated Lewis acid Sc(OTf)3. The control mechanistic evidence and DFT calculations presented a Pd/ Sc/Bri nsted acid co-catalyzed addition mechanism. The triple co-catalytic system provides a strategy for the activation of vinylquinolines with a linear selectivity containing gamma-quaternary carbon, and the developed method shows a broad substrate scope varying from alkyl/aryl alcohols and amines which provides a general and rapid strategy for the quinoline-based diverse library construction.