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
Isoquinoline-based diimine ligands for Cu(II)-catalyzed enantioselective nitroaldol (Henry) reactions
作者:Michael J. Rodig、Hwimin Seo、Dimitri Hirsch-Weil、Khalil A. Abboud、Sukwon Hong
DOI:10.1016/j.tetasy.2011.05.018
日期:2011.5
A series of isoquinoline-based chiral diimine ligands are conveniently prepared via Bischler–Napieralski cyclization. The C2-symmetric diimine ligand 1a is effective in Cu(II)-catalyzedenantioselectiveHenryreactions between nitromethane and various aldehydes (11 examples), showing 50–89% yield and 75–93% ee.
Cu-catalyzed asymmetric Henry reaction promoted by chiral camphor Schiff bases
作者:Tangqian Jiao、Jingxuan Tu、Gaoqiang Li、Feng Xu
DOI:10.1016/j.molcata.2016.02.004
日期:2016.5
Abstract Five novel chiral camphor Schiffbases have been synthesized and utilized as ligands in asymmetric Henry reaction between nitromethane and aldehydes. The diastereoisomeric Schiffbases 5a and 5a' were separated successfully and gave completely different absolute configurations in the reaction. The reactions were carried out with CuCl-Schiff base 5a complex under mild condition with good yields
Diamine-Tethered Bis(thiourea) Organocatalyst for Asymmetric Henry Reaction
作者:Jan Otevrel、Pavel Bobal
DOI:10.1021/acs.joc.7b00079
日期:2017.8.18
We have developed a novel multifunctional C2-symmetric biphenyl-based diamine-tethered bis(thiourea) organocatalyst, which was tested in the asymmetric Henry reaction. Under thoroughly optimized conditions, the catalyst provided exceptionally high yields and excellent enantioselectivities especially for electron-deficient aromatic and heterocyclic substrates. Due to a high affinity of the catalyst