The ω-acyloxy n-propylidenephosphoranes give 2,3-dihydrofurans in toluene, and cyclopropylcetones in t-butanol. The mechanism of these reactions was investigated; formation of cyclopropylketone does not result from intramolecular condensation but from two intermolecular condensations.
A robust direct enol ether metalation–Negishi coupling using heteroaryl halides catalyzed by the palladium-Cy-DPEPhos system is reported. This method, which was demonstrated with a broad substrate scope, is a highly complementary method to the existing Heck coupling of synthesizing challenging α-heteroaryl-α-alkoxy alkenes.