Organic reactions catalyzed by rhenium carbonyl complexes

Rhenium carbonyl complex-catalyzed synthetic organic reactions are discussed. Kusama and Narasaka reported that a rhenium complex, ReBr(CO) ₅, which catalytically promotes Friedel-Crafts acylation. Kusama, Iwasawa, and co-workers reported that the rhenium complex ReCl(CO)₅ catalyzes tandem cyclization of ω-ω-acetylenic dienol silyl ethers. Farona and Greenlee reported that a mixture of catalytic amounts of ReX(CO) ₅ (X = Cl or Br) and EtAlCl₂ promotes olefin metathesis of terminal and internal olefins. The rhenium catalyst is found to promote C-H bond activation followed by insertion of an acrylate, intramolecular nucleophilic cyclization, and finally the elimination of aniline to give the cyclopentadiene derivative, which then complexes to the metal. Fuchikami and co-workers reported the reduction of carboxylic acids to alcohols by dihydrogen.