Iron-catalyzed [2 + 2 + 2] intermolecular cycloaddition of trifluoromethyl group substituted unsymmetrical internal alkynes afforded the corresponding trifluoromethyl group substituted benzene derivatives in high yield with excellent selectivity.
Highly regioselective cobalt-catalyzed [2+2+2] cycloaddition of fluorine-containing internal alkynes to construct various fluoroalkylated benzene derivatives
cobalt-catalyzed [2+2+2] cycloaddition using fluorine-containing alkynes was described. Cyclotrimerization of fluorinated alkynes under the influence of CoCl2(dppb) in acetonitrile at 80 °C for 3 h took place smoothly, affording the corresponding benzene derivatives in excellent yields with high regioselectivity. Additionally, intermolecular cycloaddition of fluorinated alkynes with non-fluorinated diynes
First practical synthesis of 2- or 3-fluoroalkylated indenols via cobalt-catalyzed [2 + 3] carbocyclization of fluorine-containing alkynes and 2-iodoaryl ketones
[2 + 3] Cycloaddition reaction of fluorine-containing alkynes with various 2-iodoaryl ketones in the presence of CoCl2(dppf) catalyst proceeded very smoothly to give the corresponding 2- or 3-fluoroalkylated indenols in 57–98% yields. These regioisomers could be successfully separated and obtained in a pure form. From X-ray crystallographic and NOESY analyses, major or minor regioisomers were determined