An efficient Sonogashira coupling of a heterocyclic phosphonium salt with a terminal alkyne via C–P bond cleavage was developed. The reactions proceeded smoothly in the presence of palladium catalyst, copper­(I) iodide, and N,N-diisopropylethylamine (DIPEA) in N-methyl-2-pyrrolidone (NMP) at 100 °C for 12 h, producing the corresponding alkynyl-substituted pyridine, quinoline, pyrazine, and quinoxaline in moderate to good yields with wide substrate scope and broad functional group tolerance. In addition, gram-scale synthesis could also be achieved, and the reaction could be applied to the functionalization of alkyne-containing complex molecules derived from sugars and pharmaceutical and naturally occurring products (e.g., estrone, d-galactopyranose, menthol, and ibuprofen).

The copper­(II)-mediated ring opening/alkynylation of cyclopropanol by employing inexpensive and commercially available terminal alkyne is developed. The reactions proceeded efficiently to afford synthetically useful alk-4-yn-1-ones in moderate to good yields with good functional group tolerance. Control experiments showed that the reaction presumably proceeds via the formation of intermediates of copper homoenolate and/or alkynylcopper species.

The strong and unreactive CÀ F bond makes polyfluorocarbons extremely long-lived and potentially toxic. A successive selective and controllable C(sp 3)À F functionalization of polyfluoroalkylated ketones with Sand O-nucleophiles to enable efficient synthesis of pharmaceutically important fluorine-and sulfurcontaining polycyclic furan and chromene derivatives under transition metal-free conditions is demonstrated here. The combination of CÀ S/CÀ O coupling, aromatization, and cyclization cascade contribute to the accurate four/five C(sp 3)À F bond cleavage at two different sites of perfluoroalkyl chain. The formation of reactive quinoid intermediates and the necessity of using TBAB (tetrabutylammonium bromide) as additive and Cs 2 CO 3 as base were identified by detailed mechanistic studies.

A Pd-catalyzed C-F bond alkynylation of polyfluoroalkyl ketones with terminal alkynes has been developed. The method gives access to a range of modular perfluoroalkyl- and alkynyl-substituted furan derivatives in moderate...