pyrrolizidines and indolizidines, respectively, each with a hydroxy group on the carbon atom at the bridgehead. The cyclopropenone functions as an all-carbon 1,3-dipole equivalent towards the cyclic imine in this reaction, and the cyclic imines used include polyhydroxylated systems, thus allowing access to australine, alexine and hyacinthacine type compounds. The pyrrolizidine products contain the core of the
3-Hydroxypyrroles and 1H-pyrrol-3(2H)-ones. Part 4. Oxidation of 2-monosubstituted and 2-unsubstituted pyrrolones, with an electron spin resonance study of a dimeric intermediate
作者:Hamish McNab、Lilian C. Monahan、John C. Walton
DOI:10.1039/p29880000759
日期:——
Oxidation of 2-substituted 1H-pyrrol-3(2H)-ones in air gives 2-hydroxy derivatives, which can exist in solvent-dependent equilibrium with open-chain acyl enaminones. Oxidation of 2-unsubstitued analogues by irradiation in the presence of di-t-butyl peroxide gives rise to persistent radicals, identified as pyrrolone dimers [e.g.(21)] by e.s.r. spectroscopy. The formation of the various products is rationalised