Spiro-annulation of barbituric acid derivatives and its analogs by ring-closing metathesis reaction

Barbituric acid 1 and related β-dicarbonyl compounds were dialkenylated under the phase-transfer catalyst [e.g., benzyltriethylammonium chloride (BTEAC)] conditions to generate the diallylated products. These diallylated products were subjected to the ring-closing metathesis (RCM) reaction to deliver the corresponding spiro-annulated derivatives.