Pd-catalyzed C-H activation and cross-coupling with potassium styryltrifluoroborates
Conjugated enynes are common carbon moieties in natural products, pharmaceuticals, and in industrial ingredients. The recent success of Suzuki type reactions involving potassium organotrifluoroborates salts in cross-coupling chemistry attracts us to explore C-H activation of alkynes by transition metal catalyst and cross-coupling with potassium styryltrifluoroborates resulting into the predicted conjugated enynes. In palladium catalyzed Suzuki-Miyaura type coupling reactions involving potassium organotrifluoroborates, C-X (X = I, Br, Cl, OTf, ONf) groups are required to initiate the oxidative addition of Pd0 to produce PdII containing intermediates. The direct activation of C-H will lead the same valuable purposes by avoiding the presence of C-X in the starting material. The new reaction methodology of palladium-catalyzed C-H activation using PdCl2(dtbpf) complex as a catalyst source is a first success story of cross-coupling chemistry involving terminal alkynes, potassium styryltrifluoroborates under microwave irradiation. The synthesized compounds have been analyzed and confirmed by GC-MS, 1H NMR, 13C NMR, and 19F NMR spectroscopy study. We also attempted the same kind of cross coupling by using C(sp3)-H. This new transformation of C-H activation of alkanes and using it in cross-coupling chemistry of potassium organotrifluoroborates is yet to be established.
"Pd-catalyzed C-H activation and cross-coupling with potassium styryltrifluoroborates"
ETD Collection for Tennessee State University.