Expedient nonclassical reaction of acetylenes with ketones: Controlling the switch between bicyclic ketal and cyclopentenol formation

Abstract

The condition-controlled switch between the bicyclic ketals, 7-methylene-6,8-dioxabicyclo[3.2.1]octanes and 3-acyl-2-cyclopenten-1-ols formation during the 2:2 selfassembly of acetylenes with ketones in the presence of the KOH/DMSO suspension at 30-70 oC has been developed. The selectivity reaches ca. 100% for bicyclic ketals and 67% for cyclopentenols. Both reactions are diastereoselective.