Highly regio- and diastereoselective (3+3)-cycloannulation of carbonyl ylides and 2-(1-alkynyl)-2-alken-1-ones enabled by silver catalysis

A highly regio- and diastereoselective (3+3)-cycloannulation of in situ generated carbonyl ylides and 2-(1-alkynyl)-2-alken-1-ones enabled by silver catalysis is reported. This work is the first to describe a silver catalysed synthesis of 3,4-fused furan with an oxa-bridged motif. The scope of the reaction is broad and the oxa-bridged furan products were obtained in good to high yields and with excellent regio- and diastereoselectivities.