Gold-Catalyzed 1,2-Acyloxy Migration/Coupling Cascade of Propargyl Diazoacetates: Synthesis of Isomycin Derivatives

An efficient gold(I)-catalyzed carbocyclization reaction for the synthesis of isomycin derivatives from propargyl diazoacetates has been developed. The suggested cyclization pathway delineated the first example of a vinyl gold carbenoid species generated in situ from gold(I)-catalyzed 1,2-acyloxy migration and intercepted by a cross-coupling reaction with the remaining tethered diazo functionality. The use of protic additives was essential to regulating the reaction outcome by fine-tuning the catalytic preference of the gold(I) complex.