Readily available hydrogen bond catalysts for the asymmetric transfer hydrogenation of nitroolefins
作者:Jakob F. Schneider、Markus B. Lauber、Vanessa Muhr、Domenic Kratzer、Jan Paradies
DOI:10.1039/c1ob05059a
日期:——
focuses on readily accessible thiourea hydrogen bond catalysts derived from amino acids, whose steric and electronic features are modulated by their degree of substitution at the carbinol carbon center. These catalysts were applied in the asymmetric transfer hydrogenation of nitroolefins furnishing the chiral products in up to 99% yield and 86% enantiomeric excess. The proposed catalyst's mode of action
highly enantioselectiveconjugateaddition of a variety of arylboronic acids to β-nitroacrylates is reported to provide optically active α-aryl β-nitropropionates in up to 70% yields and >99.5% ee’s, which are useful building blocks for preparing chiral β2-amino acids. The applicability of this transformation is demonstrated by converting 3aa into the β2-amino acid 5 and transforming 3ap to β-amino ester