Home  About us  Contact
 

Alkyne Insertion (alkyne + insertion)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

Formal Alkyne Insertion into Alkoxycarbene Complexes: Simple Access to Enantiopure Group 6 Alkynyl(alkoxy)carbene Complexes.

CHEMINFORM, Issue 49 2005
Jose Barluenga
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Nickel-Catalyzed Intermolecular Alkyne Insertion into Cyclobutanones.

CHEMINFORM, Issue 39 2005
Masahiro Murakami
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Two Distinct Mechanisms of Alkyne Insertion into the Metal,Sulfur Bond: Combined Experimental and Theoretical Study and Application in Catalysis

CHEMISTRY - A EUROPEAN JOURNAL, Issue 7 2010
Valentine
Abstract The present study reports the evidence for the multiple carbon,carbon bond insertion into the metal,heteroatom bond via a five-coordinate metal complex. Detailed analysis of the model catalytic reaction of the carbon,sulfur (CS) bond formation unveiled the mechanism of metal-mediated alkyne insertion: a new pathway of CS bond formation without preliminary ligand dissociation was revealed based on experimental and theoretical investigations. According to this pathway alkyne insertion into the metal,sulfur bond led to the formation of intermediate metal complex capable of direct CS reductive elimination. In contrast, an intermediate metal complex formed through alkyne insertion through the traditional pathway involving preliminary ligand dissociation suffered from "improper" geometry configuration, which may block the whole catalytic cycle. A new catalytic system was developed to solve the problem of stereoselective SS bond addition to internal alkynes and a cost-efficient Ni-catalyzed synthetic procedure is reported to furnish formation of target vinyl sulfides with high yields (up to 99,%) and excellent Z/E selectivity (>99:1). [source]

Tertiary Carbinamine Synthesis by Rhodium-Catalyzed [3+2] Annulation of N-Unsubstituted Aromatic Ketimines and Alkynes

CHEMISTRY - A EUROPEAN JOURNAL, Issue 8 2010
Zhong-Ming Sun Dr.
Abstract A convenient and waste-free synthesis of indene-based tertiary carbinamines by rhodium-catalyzed imine/alkyne [3+2] annulation is described. Under the optimized conditions of 0.5,2.5,mol,% [{(cod)Rh(OH)}2] (cod=1,5-cyclooctadiene) catalyst, 1,3-bis(diphenylphosphanyl)propane (DPPP) ligand, in toluene at 120,°C, N-unsubstituted aromatic ketimines and internal alkynes were coupled in a 1:1 ratio to form tertiary 1H -inden-1-amines in good yields and with high selectivities over isoquinoline products. A plausible catalytic cycle involves sequential imine-directed aromatic CH bond activation, alkyne insertion, and a rare example of intramolecular ketimine insertion into a RhI,alkenyl linkage. [source]

Two Distinct Mechanisms of Alkyne Insertion into the Metal,Sulfur Bond: Combined Experimental and Theoretical Study and Application in Catalysis

CHEMISTRY - A EUROPEAN JOURNAL, Issue 7 2010
Valentine
Abstract The present study reports the evidence for the multiple carbon,carbon bond insertion into the metal,heteroatom bond via a five-coordinate metal complex. Detailed analysis of the model catalytic reaction of the carbon,sulfur (CS) bond formation unveiled the mechanism of metal-mediated alkyne insertion: a new pathway of CS bond formation without preliminary ligand dissociation was revealed based on experimental and theoretical investigations. According to this pathway alkyne insertion into the metal,sulfur bond led to the formation of intermediate metal complex capable of direct CS reductive elimination. In contrast, an intermediate metal complex formed through alkyne insertion through the traditional pathway involving preliminary ligand dissociation suffered from "improper" geometry configuration, which may block the whole catalytic cycle. A new catalytic system was developed to solve the problem of stereoselective SS bond addition to internal alkynes and a cost-efficient Ni-catalyzed synthetic procedure is reported to furnish formation of target vinyl sulfides with high yields (up to 99,%) and excellent Z/E selectivity (>99:1). [source]