A highly efficient N,N′-dioxide/Gd(III) complex has been developed for the enantioselective conjugate addition of nitroalkanes to α,β-unsaturated pyrazolamides. Under mild reaction conditions, a series of γ-nitropyrazolamides were obtained in good to excellent yields (up to 99%) with excellent enantioselectivities (up to 99% ee). What’s more, the optically active products could be easily transformed
Highly enantioselective Michael addition of α-nitroacetate to α,β-unsaturated pyrazolamide catalyzed by a bifunctional squaramide
作者:Yingying Liu、Ling Ye、Zhichuan Shi、Xuejun Yang、Zhigang Zhao、Xuefeng Li
DOI:10.1002/chir.23023
日期:2018.12
A highly enantioselective (91‐ > 99% ee) Michaeladdition of α‐nitroacetate to α,β‐unsaturated pyrazolamide was developed in the presence of a bifunctional squaramide. Satisfactory isolated yields (42%‐99%) have been achieved with a wide range of α,β‐unsaturated pyrazolamides, albeit acceptor of this type displayed poor reactivity in the precedent reports. The adducts resulting from this protocol are