137053-64-6Relevant articles and documents
?-Facial stereoselectivity in the Diels-Alder reactions of benzene oxides
Gillard, James R.,Newlands, Michael J.,Bridson, John N.,Burnell, D. Jean
, p. 1337 - 1343 (2007/10/02)
The Diels-Alder reactions of N-phenylmaleimide and dimethyl acetylenedicarboxylate with benzene oxide (1,3,5-cyclohexatriene 1,2-oxide, 3) and its more substituted derivatives 1,2-dimethyl-1,3,5-cyclohexatriene 1,2-oxide (7) and 10-oxatricyclodeca-2,4-diene (11) in a kinetic manner gave exclusively products of addition anti to the plane-nonsymmetrical oxygen.The structures of the adducts were determined unequivocally by nuclear Overhauser enhancements in their 1H nuclear magnetic resonance spectra and by X-ray crystallographic methods.The ?-facial stereoselectivity was rationalized in terms of unfavorable orbital interactions, steric hindrance between the dienophile and the syn face of benzene oxide, and ?-donation by the oxygen. Key words: cycloaddition, Diels-Alder, syn-anti, ?-facial stereoselectivity, benzene oxide.
