title: Co-complexes derived from alkene insertion to alkyne-dicobaltpentacarbonyl complexes: insight into the regioselectivity of pauson-khand reactions of cyclopropenes.
abstract: Described are the X-ray crystallographic and spectral properties of Co-complexes that were isolated from two Pauson-Khand reactions of chiral cyclopropenes. These are the first examples of isolated Co-complexes derived from the putative alkene-insertion intermediates of Pauson-Khand reactions. The binuclear Co-complexes are coordinated to mu-bonded, five-carbon "flyover" carbene ligands. It is proposed that the complexes result from cyclopropane fragmentation subsequent to alkene insertion. The observation of these metal complexes provides a rationale for the origin of regioselectivity in Pauson-Khand reactions of cyclopropenes.
authors.affiliation: Brown Laboratory, Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA.
authors.forename: Mahesh K
authors.initials: MK
authors.lastname: Pallerla
authors.forename: Glenn P A
authors.initials: GP
authors.lastname: Yap
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Fox
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D000480:Alkynes / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003517:Cyclopentanes / Q000737:chemistry; D003521:Cyclopropanes / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009941:Organomercury Compounds / Q000737:chemistry*; D013055:Spectrophotometry, Infrared
chemical_list: D000475:Alkenes; D000480:Alkynes; D003517:Cyclopentanes; D003521:Cyclopropanes; D009941:Organomercury Compounds; D003035:Cobalt; C021985:cyclopropene; C013905:cyclopentenone