Regiochemistry on Photoamination of Stilbene Derivatives with Ammonia via Electron Transfer

Article abstract of DOI:10.1021/jo00031a010

The regiochemistry of photoamination of 1,2-diarylethene (1) with ammonia in the presence of p-dicyanobenzene (DCNB) has been investigated.The photoamination of stilbene and p,p'-dimethoxystilbene gave 1-amino-1,2-diphenylethane and 1-amino-1,2-bis(p-methoxyphenyl)ethane, respectively.The photoamination of unsymmetric 1-aryl-2-phenylethene having an alkoxy group on the para position occurred selectively to give 1-amino-2-aryl-1-phenylethane.On the other hand, the photoamination of 1-aryl-2-phenylethene having a methyl and chloro group on the para position or methoxy group on the meta and ortho positions gave both 1-amino-2-aryl-1-phenylethane and 1-amino-1-aryl-2-phenylethane.The regiochemistry is related with the distribution of positive charge in the cation radicals of 1 generated from photochemical electron transfer to DCNB.