Q In 3 n-1 4 n-2 was complete within 15 min at room temperature giving the epoxide and acetone as the only products. The present procedure avoids the presence of electrophiles or nucleophiles. Solvent and excess dimethyldioxirane were removed by evaporation in a stream of nitrogen to leave 2 as a. solid which could be recrystallized from acetone and methylene ch10ride. I~ The crystalline material underwent a phase transition near 230 OC ...