General palladium-catalyzed cross coupling of cyclopropenyl esters

We report a method for the direct palladium-catalyzed cross coupling reactions of cyclopropenyl esters bearing a variety of substitution patterns with Csp² iodides. This reaction is largely insensitive to the electronic nature of the coupling partner. Tetramethylammonium acetate, a halide sequestrant, was exceptionally effective as an organic base. An observed KIE of 2.5 revealed C-H bond cleavage to be involved in the turnover-limiting step. This method enables the rapid assembly of cyclopropenes whose preparation previously required the use of toxic tin and arsenic reagents.