Asymmetric Synthesis of Fused Bicyclic<i>N,O</i>- and<i>O,O</i>-Acetals via Cascade Reaction by Gold(I)/<i>N,N</i>′-Dioxide-Nickel(II) Bimetallic Relay Catalysis
作者:Bowen Hu、Jun Li、Weidi Cao、Qianchi Lin、Jian Yang、Lili Lin、Xiaohua Liu、Xiaoming Feng
DOI:10.1002/adsc.201800576
日期:2018.8.6
hetero‐Diels‐Alder cascade reaction of β,γ‐unsaturated α‐ketoesters with alkyl amides or alcohols were accomplished. The process was based on the utilization bimetallic catalyst system with achiral gold(I) catalyst and chiral N,N′‐dioxide/Ni(II) catalyst, delivering a variety of fused bicyclic N,O‐acetals or O,O‐acetals in up to 99% yield and 99% ee with >19:1 dr under mild reaction conditions. Based
β,γ-不饱和α-酮酸酯与烷基酰胺或醇的高效催化不对称环化/反电子需求杂Diels-Alder级联反应得以实现。该工艺基于利用非金属手性金(I)催化剂和手性N,N'-二氧化物/ Ni(II)催化剂的双金属催化剂体系,可在其中提供各种稠合的双环N,O-缩醛或O,O-缩醛。在温和的反应条件下,以> 19:1 dr可获得高达99%的收率和99%ee。基于控制实验和先前的研究,提出了双金属继电器催化级联反应的可能反应途径。