Combination Of Phosphine Research Articles

Efficient Construction of 3‐Fluoroalkylated Oxindoles Enabled by Zwitterion Catalysis

Abstract3,3‐Disusbtituted oxindoles are important compounds in organic synthesis, and methods to access this class of compounds have always been sought after. Herein, we have identified a new method where a zwitterion generated using a combination of phosphine and para‐quinone methide could efficiently catalyze the 1,6‐conjugate addition of α‐fluoro‐β‐ketoamides to isatin‐derived para‐quinone methides to access 3‐fluoroalkylated oxindoles. It was further shown that the methodology could be extended to arylaldehyde‐derived p‐QMs. Moreover, one of the conjugate addition products was efficiently transformed into oxoindolinyl fluoroacetamide derivative through a K2CO3 mediated deacylation reaction.

Organometallic deposition of ultrasmooth nanoscale Ni film

Deposition of nanoscale and smooth Ni film is challenging using wet chemistry. Herein, organometallic (OM) Ni precursor yields colloidal nanoparticles which self-assemble into thin metallic film with uniform thickness on large scale. More precisely, we report on the one-pot synthesis and self- assembly of a monolayer of amorphous Ni nanopar- ticles on areas as large as 10 lm 2 , with a thickness as low as 10 nm and a roughness of 1.1 nm (RMS). Interestingly, the reactivity of different complexes, whether OM, namely Ni (g 4 -C8H12)2 or metal- organic, namely Ni(acac)2, orthogonally depends on whether the reaction is performed on a silicon wafer or in solution. Only the combination of phosphine and amine ligands with OM precursor effectively controls the homogeneity of the film on large scale, while phosphine ligands result in P doping of the amorphous Ni.

Synthesis of Triphosphorous Bidentate Phosphine–Phosphoramidite Ligands: Application in the Highly Enantioselective Hydrogenation of ortho‐Substituted Aryl Enamides

New couple: A novel combination of phosphine and phosphoramidite groups is applied to the preparation of pseudo-C2-symmetric triphosphorous bidentate phosphine–phosphoramidite ligands 1. Unprecedented enantioselectivities toward ortho-substituted aryl enamides and a 1-naphthylenamide in Rh-catalyzed hydrogenation reactions are obtained.

Reduction of 1,2‐Dicarbonyl Compounds Mediated by the Combination of Phosphine and Lewis Acid.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Reductive Claisen‐Type Condensation Promoted by the Combination of Phosphine and Lewis Acid.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Reduction of 1,2-Dicarbonyl Compounds Mediated by the Combination of Phosphine and Lewis Acid

The combination of Ph3P/AlBr3 effectively promoted the reduction of several 1,2-dicarbonyl compounds in the presence of water (1.0 equiv) and the corresponding α-hydroxy carbonyl compounds were obtained in good yields.

Reductive Claisen-Type Condensation Promoted by the Combination of Phosphine and Lewis Acid

The Ph3P/TiCl4 combination was found to be an effective promoter for the Claisen-type condensation of α-bromothioesters. Both in the case of self-condensation and crossed-type reactions, corresponding β-ketothioesters were obtained in good yields.

The influence of the ring substituent, R, on the substitution of carbonyl groups by phosphine ligands in [Co2{µ-PPh2CHCRC(O)}(µ-PPh2)(CO)4](R = H, Ph or SiMe3)

The room-temperature reaction of the complexes [Co2{µ-PPh2CHCRC(O)}(µ-PPh2)(CO)4](R = H 1a, Ph 1b or SiMe31c) with 1 equivalent of PPhMe2 gave a combination of phosphine substituted products which depends on the nature of R. When R = H 1a, two isomeric monosubstituted complexes of formula [Co2{µ-PPh2CHCHC(O)}(µ-PPh2)(CO)3(PPhMe2)]2a and 3a are afforded in a ratio of approximately 1 : 1 in which the phosphine co-ordinates either at the cobalt atom π-co-ordinated by the carbon–carbon double bond (2a) or at the cobalt to which the PPh2 and CO groups of the metallacyclic ligand are σ bonded (3a). When R = Ph 1b, the corresponding monosubstituted derivatives, [Co2{µ-PPh2CHCPhC(O)}(µ-PPh2)(CO)3(PPhMe2)]2b and 3b are formed together with traces of the disubstituted complex [Co2{µ-PPh2CHCPhC(O)}(µ-PPh2)(CO)2(PPhMe2)2]4b. In the case of R = SiMe31c, only the monosubstituted isomer [Co2{µ-PPh2CHC(SiMe3)C(O)}(µ-PPh2)(CO)3(PPhMe2)]3c is obtained. Conversion of the monosubstituted complexes 2a, 2b and 3a, 3b to the disubstituted complexes [Co2{µ-PPh2CHCRC(O)}(µ-PPh2)(CO)2(PPhMe2)2](R = H 4a or Ph 4b) takes place on thermal reaction of respectively 2a, 3a and 2b, 3b with a further equivalent of PPhMe2. An X-ray crystal structural determination has been performed on complex 4a and reveals a pseudo-axial/cis arrangement of the phosphine groups which are located one on each cobalt atom. The complex [Co2{µ-PPh2CHCPhC(O)}(µ-PPh2)(CO)4]1b reacted with the secondary phosphine PPh2H initially in the same way as with PPhMe2 to give isomeric species of formula [Co2{µ-PPh2CHCPhC(O)}(µ-PPh2)(CO)3(PPh2H)]2d and 3d. Thermolysis of complex 2d resulted in 42% conversion to the isomeric 3d along with traces of 1b and [Co2{µ-PPh2CHCPhC(O)}(µ-PPh2)(CO)2(PPh2H)2]4d.