Two Distinct Diazo-Diazo Cross-Coupling Reactions between α-Aryldiazo Ketones and Vinyldiazo Esters Using Gold Catalyst and Tetrabutylammonium Fluoride.

Two distinct coupling reactions of α-aryldiazo ketones with vinyldiazo esters are described using gold catalyst (5 mol %) and Bu4NF promoter (1.5 equiv), respectively. This new synthetic scheme involves a prior rearrangement of α-aryldiazo ketones to generate diarylketenes under thermal conditions whereas vinyldiazo esters serve as nucleophiles to afford isolable 4-siloxy-1-diazo-pent-4-en-2-ones. This diazo-diazo cross-coupling reaction yields highly substituted cyclopentenones using gold catalyst and substituted pyrazole derivatives with Bu4NF promoter.