Treatment of 2-methoxycarbonyl- (or 3-cyano-)allyl acetoacetates with a tertiary amine or triphenylphosphane afforded α-methylene γ-substituted δ-keto esters (or nitrile) in satisfactory yields. Various bases and nucleophiles were tested to elucidate the mechanism. The results of the study strongly suggest an intermolecular pathway involving a SN2′-decarboxylation-SN2′ cascade.
A Modular and Diastereoselective 5 + 1 Cyclization Approach to N-(Hetero)Aryl Piperidines
作者:Matthew A. Larsen、Elisabeth T. Hennessy、Madeleine C. Deem、Yu-hong Lam、Josep Saurí、Aaron C. Sather
DOI:10.1021/jacs.9b13114
日期:2020.1.15
A new general de novo synthesis of pharmaceutically important N-(hetero)aryl piperidines is reported. This protocol uses a robustly diastereoselective reductive amination/aza-Michael reaction se-quence to achieve rapid construction of complex polysubstituted ringsystems starting from widely available heterocyclic amine nu-cleophiles and carbonyl electrophiles. Notably, the diastereoselec-tivity of