A Cross-Coupling Reaction between Ortho -Substituted Aryl Iodide and Diazoester Using Tri-(2-furyl)phosphine as a Ligand of Palladium Catalyst

A palladium-complex-catalyzed cross-coupling reaction was achieved between benzyl diazo esters and aryl iodides bearing ortho-substituents, which had previously not been tolerated for such reactions. In the quest for an optimal catalyst for reactions with ortho-iodobenzaldehyde, the yields of the desired coupling compound were unsatisfactory in many catalyst systems, and the aldol reaction frequently occurred competitively. However, the catalyst prepared from Pd(dba)2 and P(2-furyl)3 promoted the cross-coupling reaction, generating α-diazophenyl acetate in excellent yield. The cross-coupling was also acceptable for aryl iodides with various ortho-substituents, delivering a variety of coupling products in moderate to good yields.