Addition reactions of aminium radicals: oxidative and non-oxidative photoaddition of nitrosoamines to non-conjugated polyenes

Abstract

The oxidative photoaddition of N-nitrosodimethylamine to various olefins gives products similar to those obtained from N-nitrodimethylamine despite certain dis-similarity in the mechanisms. The oxidative photoaddition to rrans,rrans,rrans-cyclododeca-1,5,9-triene in the presence of an excess of N-nitrosodimethylamine apparently gave good yields of the expected amino-nitrates. These were reduced by lithium aluminium hydride to afford predominantly the open-chain a,o-substituted amino-alcohol. The non-oxidative photoaddition of N-nitrosodimethylamine to hepta-l,6-diene gave small amounts of cyclized pentane derivatives whereas similar addition of bulkier N-nitrosopiperidine gave higher yields of the cyclized products. While photoadditions of N-nitrosodimethylamine to rrans,rrans,rrans-cyclododeca-l,5,9-triene failed to give a cyclization product, similar photoadditions to cis,frans-cyclodeca-1,5-diene gave a pair of epimeric alcohols derived from a stereospecifically cyclized perhydroazulenoid skeleton under oxidative conditions, and the corresponding oximes under non-oxidative conditions. The structures of these azulenoid compounds have been elucidated and the remarkable stereospecificity of addition-cyclization process is discussed.

An Organic Chemist’s Guide to N-Nitrosamines: Their Structure, Reactivity, and Role as Contaminants

“…Although fewer investigations have focused on neutral conditions, the photochemical reactions of N -nitrosamines in acidic conditions were extensively explored by Chow and co-workers in the late 1960s through the 1980s. ,,− Many of these reactions have been reviewed previously, , but are covered briefly here for completeness. Chow and co-workers found that the reactions of nitrosamines under photolytic conditions with various substrates are dominated by the reactivity of the produced aminium radical, and consequently require acidic conditions .…”