Coordinately unsaturated clusters. A novel catalytic reaction

Journal Article · Sat Jun 11 04:00:00 EDT 1983 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00349a030· OSTI ID:5485170

Burch, R R ^[1]; Shusterman, A J; Muetterties, E L; Teller, R G; Williams, J M

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1. Univ. of California, Berkeley

The dinuclear rhodium hydride )(..mu..-H)Rh(P(O-i-C/sub 3/H/sub 7/)/sub 3/)/sub 2/)/sub 2/ is a catalyst precursor for stereoselective hydrogenation of dialkylalkynes and diarylalkynes to the corresponding trans-alkenes. Both H/sub 2/ and the alkyne compete for reaction with the dimer with the respective products being (H)(..mu..-H)/sub 3/Rh/sub 2/(P(O-i-C/sub 3/H/sub 7/)/sub 3/)/sub 4/ and (..mu..-H)/sub 2/(..mu..-n/sup 2/-RC/sub 2/R)Rh/sub 2/(P(O-i-C/sub 3/H/sub 7/)/sub 3/)/sub 4/. The further reaction of the tetrahydride complex with alkyne and also the rearrangement of the n/sup 2/-alkyne complex yield a bridged vinyl derivative, (..mu..-H)(..mu..-n/sup 2/-RC=C(H)R)Rh/sub 2/(P(O-i-C/sub 3/H/sub 7/)/sub 3/)/sub 4/, 3, which has a trans arrangement of alkyl or aryl groups as established by X-ray crystallographic studies. The rate-determining step in the catalytic cycle appears to be hydrogen addition to the vinyl derivative. Competitive with hydrogen addition to the vinyl derivative is diarylalkyne addition and insertion to give the mononuclear complex (R(H)C=C(R)(R)C=CR)Rh(P)O-i-C/sub 3/H/sub 7/)/sub 3/)/sub 2/, which was also defined by an X-ray crystallographic study. The latter is a catalyst precursor for alkyne hydrogenation to form cis-alkenes. Dynamic stereochemical features of the vinyl complexes in the solution state are described as well as intermolecular alkyne exchange between free alkyne and the vinyl complexes.

• OSTI ID: 5485170
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 105:11; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ALKENES
ALKYNES
CATALYTIC EFFECTS
CHEMICAL REACTIONS
COHERENT SCATTERING
COMPLEXES
CRYSTALLOGRAPHY
DIFFRACTION
DIMERS
HYDROCARBONS
HYDROGENATION
ORGANIC COMPOUNDS
RHODIUM COMPLEXES
SCATTERING
STEREOCHEMISTRY
TRANSITION ELEMENT COMPLEXES
X-RAY DIFFRACTION