Prototropic isomerization of 1-oxaspiro[2.3]hexane-5-carbonitrile and methyl 1-oxaspiro[2.3]hexane-5-carboxylate into the corresponding 3-hydroxymethylbicyclo[1.1.0]butane-1-carboxylic acid derivatives

Epoxy derivatives of 3-methylenecyclobutane-1-carbonitrile and methyl 3-methylenecyclobutane-1-carboxylate undergo isomerization into the corresponding 3-hydroxymethylbicyclobutane-1-carboxylic acid derivatives on treatment with lithium diisopropylamide in aprotic medium.