A series of new modular bifunctional chiral thiourea organocatalysts were synthesized from natural Cinchona alkaloids and amino acids, and their performance in the aza-Henry reaction of nitroalkanes to imines, the Michaeladdition of acetylacetone to nitroolefins and the Michaeladdition of acetone to nitroolefins was investigated. Under the mild conditions, the important building blocks β-nitro amines
A Novel Bis-Thiourea Organocatalyst for the Asymmetric Aza-Henry Reaction
作者:Constantinos Rampalakos、William D. Wulff
DOI:10.1002/adsc.200800214
日期:2008.8.4
A novelbis-thiourea BINAM-based catalyst for the asymmetricaza-Henryreaction has been developed. This catalyst promotes the reaction of N-Boc imines with nitroalkanes to afford beta-nitroamines with good yields and high enantioselectivities. This catalyst has the advantage that it can be prepared in a single step from commercially available materials. A model is proposed for the catalyst action
Enantioselective aza-Henry reaction of t-Boc protected imines and nitroalkanes with bifunctional squaramide organocatalysts
作者:Dilşad Susam、Cihangir Tanyeli
DOI:10.1039/c6nj04078k
日期:——
An organocatalytic asymmetric aza-Henry reaction of t-Boc protected imines with nitroalkanes has been established by chiral acid–base type bifunctional Cinchona alkaloid/squaramideorganocatalysts. The cooperation of a quinine motif as a base and sterically encumbered squaramide (H-bond donor) enabled mostly complete conversion of a range of reactants into the corresponding aza-Henry products at room
t - Boc保护的亚胺与硝基烷烃的有机催化不对称aza-Henry反应是通过手性酸碱型双功能金鸡纳生物碱/方酰胺有机催化剂建立的。奎宁基序作为碱和空间受限的方酰胺(氢键供体)的配合,可以在室温下以良好的选择性将一系列反应物完全转化为相应的aza-Henry产品(选择性高达91%ee,10 mol)催化剂负载百分比)。
作者:Xianxing Jiang、Yifu Zhang、Lipeng Wu、Gen Zhang、Xing Liu、Hailong Zhang、Dan Fu、Rui Wang
DOI:10.1002/adsc.200900413
日期:2009.9
doubly stereocontrolled organocatalytic aza-Henry reaction of nitroalkanes to N-Boc-imines generated in situfrom a variety of substituted α-amidosulfones was investigated for the first time, in general, affording the corresponding products with high to excellent yields (up to 93% yield) and enantioselectivities (up to 98% ee), and satisfactory diastereoselectivies (anti/syn up to 98:2). Furthermore
Reversal of enantioselectivity using tethered bisguanidine catalysts in the aza-Henry reaction
作者:Helena M. Lovick、Forrest E. Michael
DOI:10.1016/j.tetlet.2008.12.058
日期:2009.3
A series of chiral guanidines were synthesized and shown to efficiently catalyze the aza-Henry reaction. Modifications of the catalyst Structure revealed important selectivity trends as well as an intriguing reversal in stereoselectivity with bisguanidine variants. These compounds were applied to the aza-Henry reaction between N-Boc imines and nitroalkanes generating the beta-nitroamines in up to 77% ee and up to 20:1 diastereoselectivity. (C) 2009 Elsevier Ltd. All rights reserved.