Enantioselective 1,4-Addition Reactions of Diphenyl Phosphite to Nitroalkenes Catalyzed by an Axially Chiral Guanidine
作者:Masahiro Terada、Takashi Ikehara、Hitoshi Ube
DOI:10.1021/ja0746619
日期:2007.11.1
A highlyenantioselective 1,4-addition reaction of nitroalkenes with diphenyl phosphite was successfully accomplished using a newly developed axiallychiral guainidine catalyst. A broad range of nitroalkenes, bearing not only aromatic but also aliphatic substituents, is applicable to the present enantioselectivereaction. The method provides an efficient protocol to synthesize enantioenriched β-amino
Thiourea catalyzed organocatalytic enantioselective Michael addition of diphenyl phosphite to nitroalkenes
作者:Ana Alcaine、Eugenia Marqués-López、Pedro Merino、Tomás Tejero、Raquel P. Herrera
DOI:10.1039/c0ob01059f
日期:——
Bifunctional thiourea catalyzes the enantioselectiveMichaeladdition reaction of diphenyl phosphite to nitroalkenes. This methodology provides a facile access to enantiomerically enriched β-nitrophosphonates, precursors for the preparation of synthetically and biologically useful β-aminophosphonic acids. DFT level of computational calculations invoke the attack of the diphenyl phosphite to the nitroolefin
An enantioselective Michael addition of diphenyl phosphonate to nitroalkenes has been developed by using a secondary amine bisthiourea catalyst to access enantiomerically enriched β-nitro phosphonates. In this reaction, molecular sieves play a key role in achieving high and reproducible yields with a high enantioselectivities of up to 99% at –10 °C. A probable mechanism for the enantioselective Michael
通过使用仲胺双硫脲催化剂获得对映体富集的 β-硝基膦酸酯,已开发出二苯基膦酸酯与硝基烯烃的对映选择性迈克尔加成。在该反应中,分子筛在 –10 °C 下以高达 99% 的高对映选择性实现高产率和重现性方面发挥着关键作用。通过核磁共振光谱研究建立了对映选择性迈克尔加成反应的可能机制。
Enantioselective Phospha-Michael Reaction of Diphenyl Phosphonate with Nitroolefins Utilizing Conformationally Flexible Guanidinium/Bisthiourea Organocatalyst: Assembly-State Tunability in Asymmetric Organocatalysis
phospha-Michael reaction of diphenyl phosphonate to nitroolefins was achieved by utilizing a 1,3-diamine-tethered guanidinium/bisthioureaorganocatalyst. The procedure is applicable to nitroolefins having various aromatic and aliphatic substituents, and enables an efficient access to phospha-Michael products with 90–98% ee. Monomeric or oligomeric active species of the catalyst can be utilized, depending
Quinidine thiourea-catalyzed enantioselective synthesis of β-nitrophosphonates: beneficial effects of molecular sieves
作者:Santhi Abbaraju、Mayur Bhanushali、Cong-Gui Zhao
DOI:10.1016/j.tet.2011.07.059
日期:2011.9
An efficient method for enantioselective synthesis of beta-nitrophosphonates via the Michael addition of diphenyl phosphite to nitroalkenes using the readily available quinidine thiourea organocatalyst has been developed. The desired beta-nitrophosphonates were obtained in good ee values. Molecular sieves were found to be crucial for achieving high reproducible yields in this reaction. (C) 2011 Elsevier Ltd. All rights reserved.