The influence of substituents on the photochemical generation and stability of 2-morpholinocyclopropanols
摘要:
By irradiation in oxygen-free ether alpha- or beta-substituted beta-morpholinopropiophenones 1a-c form the corresponding cyclopropanols 2 with 1-aryl and 2-morpholino group in a relative cis-configuration in high yields. The photocyclization of pure 1a-c enantiomers proceeds enantioselectively under these conditions. In methanol and presence of oxygen electronically excited 1c-h are converted to enaminones 3c-h via oxidation of intermediate cyclopropanols 2c-h. In the presence of electron-acceptor molecules this reaction apparently follows a SET mechanism.