Copper-catalyzed cascade reactions between alkenes or alkynes and diaryliodonium salts form carbocyclic products in a single step. Arylation of the unsaturated functional group is proposed to form a carbocation intermediate that facilitates hydride shift pathways to translocate the positive charge to a remote position and enables ring formation via a Friedel-Crafts-type reaction.

Copper-catalyzed arylation of electron rich alkynes reveals stabilized trisubstituted vinyl cation equivalents that react with pendant arene nucleophiles to form all carbon tetrasubstituted alkenes. The new process streamlines the synthesis of important medicinally relevant molecules.

A general procedure for the copper-catalyzed regioselective ring-opening of epoxides with Grignard reagents is described. The procedure developed provides robust reaction conditions which limit the formation of impurities and has been applied successfully using a series of epoxides and Grignard reagents to provide the desired products in >90% yield with excellent regioselectivity and purity.

The reaction of alkyl instead of aryl substituted alkynes with (II) under the investigated conditions does not give the corresponding alkyl substituted cyclopentenes. The conversion of an enantiomerically enriched aryl alkyne proceeds with minimal erosion of the enantiomeric excess. Compound (XIX) is further transformed to the retinoid receptor agonist BMS-189453 (XX) offering a significantly shorter synthetic route to this drug compared to previously developed ways. -(ZHANG, F.; DAS, S.; WALKINSHAW, A. J.; CASITAS, A.; TAYLOR, M.; SUERO, M. G.; GAUNT*, M. J.; J. Am. Chem. Soc. 136 (2014) 25, 8851-8854, http://dx.

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