efficient copper-catalyzed selectivetransferhydrogenation of nitriles to primary amine-boranes and secondary amines with an oxazaborolidine–BH3 complex is reported. The selectivity control was achieved under mild conditions by switching the solvent and the copper catalysts. More than 30 primary amine-boranes and 40 secondary amines were synthesized via this strategy in high selectivity and yields of up to
Self-condensation of primaryamines to symmetrically substituted secondary amines could efficiently be promoted by an inexpensive supported copper catalyst, Cu/Al2O3, easily prepared by the reduction of the hydroxide precursor, Cu(OH)x/Al2O3. Various kinds of structurally diverse primaryamines including benzylamine, picolylamine, and aliphatic amine derivatives could selectively be converted into
廉价的负载型铜催化剂Cu / Al 2 O 3可通过还原氢氧化物前体Cu(OH)x / Al 2 O 3轻松制备,从而有效地促进伯胺向对称取代的仲胺的自缩合。各种结构不同的伯胺,包括苄胺, 苦瓜胺,并且脂肪族胺衍生物可以选择性地转化为相应的仲胺,且产率中等至优异,而在Ar或H 2的1 atm中没有任何助催化剂,例如碱和稳定的配体。与Ar中的反应相比,H 2中的反应对所需仲胺的选择性更高。H 2的作用是促进N-烷基亚胺的氢化和稳定活性Cu(0)物种。另外,在Cu / Al 2 O 3的存在下,可以通过伯胺与醇的N-烷基化和醛的还原胺化来有效地合成不对称取代的仲胺。观察到的催化确实是非均质的,并且回收的Cu / Al2 O 3催化剂可再用于自冷凝,而不会显着降低其催化性能。已经提出了涉及伯胺的脱氢和缩合为N-烷基亚胺然后氢化的反应机理,即所谓的“借用氢途径”。
RAPID REDUCTION OF NITRILES TO PRIMARY AMINES WITH NICKEL BORIDE AT AMBIENT TEMPERATURE[1]
作者:Jitender M. Khurana、Gagan Kukreja
DOI:10.1081/scc-120003619
日期:2002.1
ABSTRACT Reduction of a variety of nitriles to their corresponding primaryamines can be achieved with nickel boride generated in situ in dry ethanol at ambient temperature. The reductions are very rapid and chemoselective.
Iron-catalyzed intramolecular C-H amination of aliphatic azides has recently emerged as a powerful tool for the preparation of nitrogen heterocycles. This paper reports that α-azidyl amides can be converted in high efficacy to imidazolinone compounds via intramolecular C(sp3)-H amination by the action of a simple catalytic system composed of FeCl2 and a β-diketiminate ligand. The reactions provide
Guanidine-catalyzed enantioselective desymmetrization of meso-aziridines
作者:Yan Zhang、Choon Wee Kee、Richmond Lee、Xiao Fu、Julian Ying-Teck Soh、Esther Mun Foong Loh、Kuo-Wei Huang、Choon-Hong Tan
DOI:10.1039/c0cc05840h
日期:——
An amino-indanol derived chiral guanidine was developed as an efficient Brønsted base catalyst for the desymmetrization of meso-aziridines with both thiols and carbamodithioic acids as nucleophiles, which provided 1,2-difunctionalized ring-opened products in high yields and enantioselectivities.