We have studied the regioselectivity of Michael type additions on tropones attached to quinoxalines, i.e. dialkoxycarbonyl quinoxalinotropones. We used carbon nucleophiles (ethyl malonate and malononitrile), oxygen nucleophiles (sodium methoxide), sulphur nucleophiles (methyl and benzyl mercaptans), and nitrogen nucleophiles (methyl and phenylhydrazine, aniline). We have shown that, in general, these reactions lead to 1,4-monoadditions or to bridged products arising from a bis-1,4-addition process. We have determined the structures of the complexes obtained by comparison to the work of Fohlisch etal. in the homoaromatic series. For the case of substituted hydrazines, we present some evidence on the rearrangement mechanisms proposed by these authors. [Journal translation]
Efficient methodology for alkylation of vinylnitroso compounds with carbon nucleophiles
