152957-08-9Relevant academic research and scientific papers
Photocatalyzed Triplet Sensitization of Oximes Using Visible Light Provides a Route to Nonclassical Beckmann Rearrangement Products
Zhang, Xiao,Rovis, Tomislav
supporting information, p. 21211 - 21217 (2021/12/27)
Oximes are valuable synthetic intermediates for the preparation of a variety of functional groups. To date, the stereoselective synthesis of oximes remains a major challenge, as most current synthetic methods either provide mixtures of E and Z isomers or furnish the thermodynamically preferred E isomer. Herein we report a mild and general method to achieve Z isomers of aryl oximes by photoisomerization of oximes via visible-light-mediated energy transfer (EnT) catalysis. Facile access to (Z)-oximes provides opportunities to achieve regio- and chemoselectivity complementary to those of widely used transformations employing oxime starting materials. We show an enhanced one-pot protocol for photocatalyzed oxime isomerization and subsequent Beckmann rearrangement that enables novel reactivity with alkyl groups migrating preferentially over aryl groups, reversing the regioselectivity of the traditional Beckmann reaction. Chemodivergent N- or O- cyclizations of alkenyl oximes are also demonstrated, leading to nitrones or cyclic oxime ethers, respectively.
Dioxime oxalates; new iminyl radical precursors for syntheses of N-heterocycles
Portela-Cubillo, Fernando,Lymer, James,Scanlan, Eoin M.,Scott, Jackie S.,Walton, John C.
supporting information; experimental part, p. 11908 - 11916 (2009/04/06)
Symmetrical and unsymmetrical dioxime oxalates were prepared by treatment of oximes with oxalyl chloride. UV photolysis of these precursors was found to be an atom-efficient way of generating iminyl radicals. The process was most efficient for dioxime oxalates having aryl substituents attached to their C{double bond, long}N bonds. The method was useful for EPR spectroscopic study of iminyl and iminoxyl radicals. Photolyses in toluene solution, of dioxime oxalates containing alkenyl acceptor groups, yielded unsaturated iminyl radicals that ring closed to afford 3,4-dihydro-2H-pyrroles in good yields. Dioxime oxalates with biphenyl substituents also released iminyl radicals that ring closed onto the aromatic acceptor groups and, in acetonitrile solution, this approach provided a useful and atom-efficient method of making substituted phenanthridines.
A new method for the generation and capture of iminyl radicals
Boivin, Jean,Schiano, Anne-Marie,Zard, Samir Z.,Zhang, Haiwen
, p. 4531 - 4534 (2007/10/03)
Iminyl radicals can be generated from ketoxime esters and captured by an internal olefin; the sequence may be terminated in a variety of ways depending on the nature of the ensuing carbon radical and the added external trap.
Ring-closure Reactions of Alkenyl Oximes Induced by Persulfate Anion Oxidation of Diphenyl Diselenide. Formation od 1,2-Oxazines and Cyclic Nitrones
Tiecco, Marcello,Testaferri, Lorenzo,Tingoli, Marco,Bagnoli, Luana,Marini, Francesca
, p. 1989 - 1994 (2007/10/02)
A strongly electrophilic phenylselenenylating agent is produced from the reaction of diphenyl diselenide with ammonium persulfate, in the presence of trifluoromethanesulfonic acid, in acetonitrile or nitromethane, at room temperature.This reagent induces
