87618-62-0Relevant academic research and scientific papers
The Cycloaddition of α-Nitrosostyrenes to Olefins. Investigations of the Scope and Mechanism of the Reaction
Davies, David E.,Gilchrist, Thomas L.,Roberts, Tony G.
, p. 1275 - 1282 (2007/10/02)
Cycloaddition of α-nitrosostyrene (1a) to several substituted styrenes is shown to give 3-phenyl-5,6-dihydro-4H-1,2-oxazines (2) in moderate yield.Reactions with 4-nitro-α-nitrosostyrene (1b) give better yields of the corresponding adducts (3).The preferred conformations of the adducts are deduced from their n.m.r. spectra.The observed regio- and stereo-selectivities of the addition are interpreted in terms of one-step addition in which the olefins act as the donor components.The first example of a formal 1,3-dipolar addition of a vinyl nitroso compound is provided by the formation of the nitrone (5) as a minor product of the reaction of α-nitrosostyrene with 2-methoxypropene.The relative yield of this nitrone is not increased by the change to a more polar solvent, nor by the use of α-bromoacetophenone anti-oxime in place of the usual syn-isomer as the precursor of α-nitrosostyrene.It is suggested that this, and other minor products (4) isolated from the cycloadditions, may be formed because of steric inhibition of the usual Diels-Alder-type process.
