One-Pot Conversion of Aldehydes and Aryl Halides to Disubstituted Alkynes via Tandem Seyferth-Gilbert Homologation/Copper-Free Sonogashira Coupling.

A practically convenient protocol has been developed to convert a mixture of an aldehyde, aryl halide, and the Bestmann-Ohira reagent into disubstituted acetylene via a successive addition of base (Cs2CO3) and a Pd(II) catalyst, allowing sufficient time after addition of each of these reagents for the tandem processes (Seyferth-Gilbert homologation and Sonogashira coupling) to occur. Notably, for the latter reaction, no copper catalyst was required.