Catalyst-free diazo cross-coupling to access useful 3(2 H )-furanone derivatives.

Catalyst-free synthesis of 3(2 H )-furanone derivatives has been achieved from metal-free cross-coupling of α-diazo ester and α-aryldiazo ketones. This reaction sequence comprises a prior Wolff rearrangement of α-aryldiazo ketones to 2-arylketenes, which are trapped in situ with α-diazo esters to form cyclopropanones before undergoing oxa-Nazarov cyclization.