Nucleophilic ring opening of imidazolone activated donor–acceptor cyclopropanes with alcohols

Imidazolone-activated donor–acceptor cyclopropanes undergo alcohol-assisted ring opening under the co-action of p-toluenesulfonic acid. Under the optimized conditions, cyclopropanes and alcohols are coupled in 1,3-fashion with the retention of heterocyclic fragment. Substrates with aromatic donor groups provide the addition products in 75–99% yields as mixtures of two diastereomers.