Reactivity of differentially substituted bis(diazo) esters in rhodium(II) mediated O-H insertion reactions

Selective catalysed decompositions of one diazo group in the presence of another are discussed. A range of bis(diazo) compounds was prepared in which the two diazo groups are differentially substituted. Rhodium(II) acetate catalysed decomposition in the presence of methanol resulted in exclusive O-H insertion reaction at the more reactive diazo group, the less reactive diazophosphonate remaining intact. With the more active rhodium(II) trifluoroacetamide as catalyst, both diazo groups decomposed simultaneously. (C) 1998 Elsevier Science Ltd. All rights reserved.