Rearrangements accompanying oxidative photoaddition of nitrosamines to bicyclo[2.2.1]heptadiene, cyclo-octa-1,5-diene, and cyclohexa-1,3-diene

Abstract

Oxidative photoaddition of N-nitrosodimethylamine to bicyclo[2.2.1 ]heptadiene, cyclo-octa-1,5-diene, and cyclohexa-1,3-diene gives good yields of aminonitro-oxyalkanes. The allylic nitrate esters derived from cyclohexa-1,3-diene were too unstable to be isolated, but the 1,5-homoallylic adducts to bicyclo[2.2.1]heptadiene were stable nitrate esters and were isolated as the exo- and endo-isomers. The adducts derived from cyclo-octa-1,5-diene were cis-and trans-isomers in which the formerunderwent transannular rearrangement to give oxabicylic compounds while the latter was stable enough to be isolated as the trans-1,2-amino-nitrate ester. The primary photoaddition products are assumed to be the peroxynitrites which undergo a rapid heterolytic rearrangement. A participation of the transannular π-bond during this heterolytic rearrangement is probably the key step in the formation of the oxabicyclic compounds.