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 trans,trans,trans-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 α,ω-substituted amino-alcohol. The non-oxidative photoaddition of N-nitrosodimethylamine to hepta-1,6-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 trans,trans,trans-cyclododeca-1,5,9-triene failed to give a cyclization product, similar photoadditions to cis,trans-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.