Polycyclic bridgehead acetals with enol functionality: one-pot assembly from aliphatic ketones and acetylene in KOH/DMSO suspension

Abstract Aliphatic and cycloaliphatic ketones undergo selective multi-site cascade C–H functionalization with acetylene in the KOH/DMSO superbase suspension under mild conditions (70–80 °C, 0.5–1.0 h) to afford in one synthetic operation polycyclic bridgehead acetals with enol functionality, [methylene-6,8-dioxabicyclo[3.2.1]octanes] (the isolated yields reach 84%).