The intramolecular reaction between a diazoalkane group and an ester group: the second example

Abstract

The isomeric nitroso-lactams, cis- and trans-9-hydroxy-4-nitroso-4-azahomoadamantan-5-ones (11) and (13), have been synthesised and treated with sodium methoxide. The major products were the unexceptionable solvolysis products, the methyl cis- and trans-9-hydroxybicyclo[3.3.1]non-7-ene-3-endo-carboxylates, which were actually isolated as their dihydro-derivatives (27) and (29). In the latter case, methyl 9-oxatricyclo[5.2.1.0^3,8]decane-5-endo-carboxylate (28) was also formed. The minor products, the methyl trans- and cis-9-hydroxynoradamantane-3-carboxylates (12) and (14), respectively, were the result of a diazoalkane ester insertion reaction. The configurations of the nitroso-lactams were determined directly from n.m.r. spectra, and the configurations of the products were determined from the trisdipivaloylmethanatoeuropium(III)-shifted n.m.r. spectra.

The low yield of these products is evidently a consequence of the low yield of the diazoalkane. The diazoalkane ester insertion reaction, however, is so favoured that all the diazoalkane formed is converted into the noradamantane, even in the absence of a protic solvent.