title: Tandem cyclization of alkynes via rhodium alkynyl and alkenylidene catalysis.
abstract: A rhodium(I)-catalyzed tandem cyclization of alkynes has been developed. The reaction allows for multiple bond formations to occur at both the alpha- and beta-positions of alkynes under mild conditions to yield a variety of fused ring systems as the products. In the presence of triethylamine and the complex derived from [Rh(COD)Cl]2 and P(4-F-C6H4)3, a terminal alkyne is converted to a rhodium alkynyl species which reacts with a tethered alkyl halide at the beta-position to provide a beta,beta-disubstituted alkenylidene complex. The rhodium alkenylidene species then undergoes additional ring closures with a range of pendent functional groups such as alkene, hydroxyl, and phenyl groups through [2 + 2] cycloaddition, nucleophilic addition, and 6pi-electrocyclization processes, respectively.
authors.affiliation: Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.
authors.forename: Jung Min
authors.initials: JM
authors.lastname: Joo
authors.forename: Yu
authors.initials: Y
authors.lastname: Yuan
authors.forename: Chulbom
authors.initials: C
authors.lastname: Lee
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D012238:Rhodium / Q000737:chemistry*
chemical_list: D000475:Alkenes; D000480:Alkynes; D012238:Rhodium