PCCP‐Catalyzed Synthesis of Tetrasubstituted Allenes Bearing Heteroaromatic Sulfenyl Group.

We report a Brønsted acid‐catalyzed synthesis of tetrasubstituted allenyl compounds decorated with heterocyclic sulfenyl group. The reaction proceeds readily from available propargylic alcohols in the presence of pentacarboxycyclopenatadienes (PCCPs) as organocatalysts. The developed strategy provides tetrasubstituted allene derivatives in high yields (from 55 to 98 %) and under mild reaction conditions. [ABSTRACT FROM AUTHOR]