Allylic halides reaction with ethyl diazoacetate

The importance of the nucleophilicity of the heteroatom for product partitioning is shown for the interaction of ethyl diazoacetate with allyl halides, e.g. formation of 29 and 30. In contrast to the result for this diazo compound, rhodium-catalyzed reaction of diethyl di-azomalonate with allyl bromide yields practically no cyclopropane [Rh2(OAc)4 diethyl al-lyl(bromo)malonate (86%) and diethyl 2-bromomethylcyclopropane-l,l-dicarboxylate (6%) RhjCCO) 72 and 10%].2 ... 

Alkyl halides that show a Dn + An mechanism (Ingold terminology SnI) in nucleophilic aliphatic substitutions can be used as electrophilic reagents in C-alkyla-tions of diazoalkanes. An example is the synthesis of ethyl 2-diazopent-4-enoate (9.18) by reaction of ethyl silver diazoacetate with 3-iodoprop-l-ene (allyl bromide) (9-14, 66% Schollkopf and Rieber, 1969). 

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