Mechanism of the carbon-carbon cleavage of acetone by the ruthenium benzyne complex (PMe3)4Ru(.eta.2-C6H4): formation and reactivity of an oxametallacyclobutane complex
作者:John F. Hartwig、Robert G. Bergman、Richard A. Andersen
DOI:10.1021/ja00164a067
日期:1990.4
Generation et caracterisation d'un intermediaire potentiel de la reaction, le complexe (methyl-4 phenyl-4)oxa-1 ruthena-2 cyclobutane
Generation et caracterisation d'un intermediaire potentiel de la reaction, le complexe (methyl-4 phenyl-4)oxa-1 ruthena-2 cyclobutane
Ambient-Temperature Carbon–Oxygen Bond Cleavage of an α-Aryloxy Ketone with Cp<sub>2</sub>Ti(BTMSA) and Selective Protonolysis of the Resulting Ti–OR Bonds
作者:Addison N. Desnoyer、Beata Fartel、K. Cory MacLeod、Brian O. Patrick、Kevin M. Smith
DOI:10.1021/om300950c
日期:2012.11.12
Reaction of Cp2Ti[η2-(CSiMe3)2] with an α-aryloxy ketone produces a Ti(IV) enolate aryloxide complex. Selective protonolysis of the enolate ligand or both Ti–OR bonds can be achieved with various acids. The reaction of the enolate aryloxide with 1-phenyl-2-phenoxyethanol is catalyzed by a mixture of NEt3 and [HNEt3]X (X = OTf, BPh4).
Mechanism of Catalytic Oxidation of Styrenes with Hydrogen Peroxide in the Presence of Cationic Palladium(II) Complexes
作者:Katherine L. Walker、Laura M. Dornan、Richard N. Zare、Robert M. Waymouth、Mark J. Muldoon
DOI:10.1021/jacs.7b05413
日期:2017.9.13
Kinetic studies, isotope labeling, and in situ high-resolution mass spectrometry are used to elucidate the mechanism for the catalytic oxidation of styrenes using aqueous hydrogen peroxide (H2O2) and the cationicpalladium(II) compound, [(PBO)Pd(NCMe)2][OTf]2 (PBO = 2-(pyridin-2-yl)benzoxazole). Previous studies have shown that this reaction yields acetophenones with high selectivity. We find that
Novel photoinduced carbon-carbon bond formation in purines
作者:Vasu Nair、Stanley D. Chamberlain
DOI:10.1021/ja00293a066
日期:1985.4
Reactions S RN1 entre l'ethyl-9 iodo-6 purine et l'enolate de diverses cetones. Mecanismes
反应 S RN1 进入 l'ethyl-9 iodo-6 purine et l'enolate de differents cetones。机制
Structure and reactions of oxametallacyclobutanes and oxametallacyclobutenes of ruthenium
作者:John F. Hartwig、Robert G. Bergman、Richard A. Andersen
DOI:10.1021/om00055a061
日期:1991.9
Structure and reactivity studies are reported with the ruthenium metallacycles prepared as described in the previous paper. A C-C cleavage reaction by an apparent beta-Me elimination pathway at 45-degrees-C is reported for the PMe3-substituted oxametallacyclobutane complex (PMe3)4Ru(OC(Me)(Ph)CH2) (1), while the analogous DMPE-substituted metallacyclobutane (DMPE)2Ru(OC(Me)(Ph)CH2) (2) is stable at 140-degrees-C. Similarly, compound 1 undergoes insertion of CO into the metal-carbon bond, while 2 is inert toward this substrate. Addition of protic acids and electrophiles leads to rapid extrusion of alpha-methylstyrene with both metallacycles. X-ray structural analysis of the acetone dianion complex (PMe3)4Ru((CH2)2CO) (17) was performed and displays a dihedral angle of 46-degrees-C in the metallacycle. In contrast, the 4,4-dimethyl-2-butanone dianion complex (PMe3)4Ru(CH2C(CHCMe3)O) (15) contains a flat metallacycle that is bound through the CH2 group and the oxygen atom. Reactivity studies with 15 showed that, unlike compounds 1 and 2, the organic portion remained intact upon addition of protic acids. The addition of 4,4-dimethyl-2-butanone led to a second C-C cleavage reaction, forming the di-tert-butylacetylacetonate complex (PMe3)3Ru(Me)(CH(COCH2CMe3)2) (19). Reactivity studies with 17 showed reversible formation of the isolable oxatrimethylenemethane complex 18, which was isolated and structurally characterized. Addition of acetone to 17 led to formation of mesityl oxide dianion complex (PMe3)4Ru(OC(Me)CHC(Me)CH) (19); mesityl oxide is presumably formed by aldol condensation at the metal center. Reactivity studies of the oxametallacyclobutene complex (PMe3)4Ru(OC(CMe3)CH) showed formation of free ketone upon addition of protic acids and insertion into the metal-oxygen bond upon addition of CO2. The metallacycle was converted to the silyl enol ether upon addition of trimethylsilane and to the free ketone following addition of H-2.