α-Acyloxynitroso dienophiles in [4+2] hetero Diels–Alder cycloadditions: mechanistic insights
摘要:
alpha-Acyloxynitroso derivatives are a class of heterodienophiles leading to valuable 3,6-dihydro-1,2-oxazines or the corresponding aminoalcohols in good yields. The discovery that a beta-oxygenated moiety led to a domino [4+2] cycloaddition/sigma(N-O) bond cleavage in the presence of a catalytic amount of Lewis acid was investigated in detail, through kinetic profiling of the reaction both in the absence and presence of a promoter. These studies showed that the role of the Lewis acid was to accelerate the sigma(N-O) bond cleavage thereby promoting a highly reproducible sequence. In addition, our preliminary results on an asymmetric version of this domino sequence are reported. (C) 2010 Elsevier Ltd. All rights reserved.
Synthesis of Cyclic Hydroxamic Acids through −NOH Insertion of Ketones
作者:Ranjan Banerjee、S. Bruce King
DOI:10.1021/ol9018198
日期:2009.10.15
Treatment of cyclobutanone or cyclopentanone with N-hydroxybenzenesulfonamide under basic conditions yields the ring-expanded cyclic hydroxamic acid in 18−69% yield. Reactions of substituted cyclobutanones give ring expanded products where the −NOH group regio- and stereoselectively inserts to the more substituted position. This expansion likely proceeds through a mechanism that includes addition of
Photo‐Mediated Intermolecular Coupling of Alkenes with Ketones via Acyloxy Nitroso Compounds
作者:Danqing Zheng、Stefanie Plöger、Constantin G. Daniliuc、Armido Studer
DOI:10.1002/anie.202016955
日期:2021.4.6
An atom‐economic intermolecular radical addition reaction of acyloxy nitroso compounds to electron‐deficient alkenes mediated by visible light is reported. The starting nitroso derivatives are readily prepared by oxidation of the corresponding oximes prepared from ketones and the overall transformation represents an oxidative coupling of a ketone with a Michael acceptor. The cascade proceeds smoothly
The reaction of lead tetra-acetate with oximes. Part I. Alicyclic and aliphatic oximes
作者:J. W. Lown
DOI:10.1039/j29660000441
日期:——
Stable free radicals obtained by the action of leadtetra-acetate on the oximes of cyclopentanone, cyclohexanone, 4-butylcyclohexanone, acetone, heptan-2-one, and heptan-4-one are tentatively assigned structures corresponding to the addition of two acetoxy groups to the CN bond of the oximes, and are characterised by their electron paramagnetic resonance (e.p.r.) spectra. The corresponding acetoxy-nitroso
Hydrolysis of Acyloxy Nitroso Compounds Yields Nitroxyl (HNO)
作者:Xin Sha、T. Scott Isbell、Rakesh P. Patel、Cynthia S. Day、S. Bruce King
DOI:10.1021/ja062365a
日期:2006.8.1
complexes inhibit nitrous oxide formation. Hydrolysis of these compounds in the presence of ferric heme complexes forms ferrous nitrosylcomplexes providing further evidence for the intermediacy of HNO. Kinetic analysis shows that the rate of hydrolysis depends on pH and the structure of the acyl group of the acyloxy nitroso compound. These compounds relax pre-constricted rat aortic rings similar to known