Photoreactions of 2-(Dialkylamino)ethyl Esters of γ-Oxo Acids via Remote Hydrogen Transfer: Influence of the Stability and Conformational Flexibility of the Biradical Intermediate on Its Chemical behavior

Article abstract of DOI:10.1246/bcsj.63.3348

2-(Dibenzylamino)ethyl 4-phenyl-3-oxobutanoate underwent photocyclization via remote hydrogen migration to give 9-membered azalactones, while 2-(dimethylamino)ethyl 4-phenyl-3-oxobutanoate gave only a polymer.Irradiation of 2-(N-methylbenzylamino)ethyl 4-phenyl-3-oxobutanoate gave azalactones via a benzylic hydrogen transfer.No azalactones via methyl hydrogen migration could be detected.The stability and conformational flexibility of biradical intermediates are important factors in the present photocyclization.