Pd-catalyzed direct coupling of indoles with carbon monoxide and alkynes: selective synthesis of linear α,β-unsaturated ketones.

A new strategy is described for the direct coupling of indoles with CO and alkynes to generate α,β-unsaturated ketones. This procedure, employing Xantphos and Pd(CH3CN)4(BF4)2, is attractive from both environmental and operational points of view and adds value to the method for the carbonylation of alkynes by using carbon nucleophiles and affording linear regioselectivity.