Urea/Transition-Metal Cooperative Catalyst for anti-Selective Asymmetric Nitroaldol Reactions
作者:Kai Lang、Jongwoo Park、Sukwon Hong
DOI:10.1002/anie.201107785
日期:2012.2.13
A cooperativecatalyst that features urea H‐bonding and a cobalt center was developed for anti‐selective asymmetric Henry reactions (see scheme). The H‐bonds of urea play a crucial role in the improvement in yield (from 30 % to 84 %), enantioselectivity (from 78 % to 96 %), and anti diastereoselectivity (from 3:1 to 48:1). A short synthesis of (1R,2S)‐methoxamine hydrochloride was also accomplished
Biphenyl-Based Bis(thiourea) Organocatalyst for Asymmetric and syn-Selective Henry Reaction
作者:Pavel Bobal、Jan Otevrel
DOI:10.1055/s-0036-1588594
日期:——
excellent enantioselectivities. The achieved high reactivity and enantioselectivity in the nitroaldol reaction of nitroalkanes with aromatic aldehydes suggests promising potential for this catalyst. Moreover, a significant syn-diastereoselectivity was observed. A scalable, efficient and chromatography-free synthesis of a new enantiopure C 2-symmetric bis(thiourea) catalyst was accomplished from a readily
A new type of L-Tertiary leucine-derived ligand: Synthesis and application in Cu(II)-catalyzed asymmetric Henry reactions
作者:Zedong Cai、Ting Lan、Pengfei Ma、Jingfang Zhang、Qingqing Yang、Wei He
DOI:10.1016/j.tet.2019.130469
日期:2019.8
of Schiff bases derivedfrom amino acids were developed as chiral ligands for Cu(II)-catalyzed asymmetric Henryreactions. The optimum ligand 7d exhibited outstanding catalytic efficiency in the Cu(II)-catalyzed asymmetric Henry additions of four nitroalkanes to different kinds of aldehydes to produce 76 desired adducts in high yields (up to 96%) with excellent enantioselectivities, up to 99% enantiomeric
A new series of Schiff bases derived from Cinchona alkaloids were developed as chiral ligands for the copper(II)-catalyzed asymmetricHenry reaction. The optimized catalyst can promote the Henry reaction of both aromatic and aliphatic aldehydes with nitromethane or nitroethane. Those reactions can afford the chiral β-nitro alcohol adducts with high enantioselectivities.
The steric and electronic properties of chiral Schiff base ligands derived from cinchona alkaloids were evaluated in asymmetric Henry reactions. Amongst these, the stericallyhindered ligand 2 showed outstanding catalytic efficiency in the Cu(II) catalyzed asymmetric addition of nitroalkanes to a variety of aldehydes to afford the desired adducts in high yields (up to 97%) with excellent enantioselectivities