Ni, Co, and Mo-metal-catalyzed alkynes hydrostannations using Bu(3)SnCl/PMHS/KF/18-crown-6 as an in situ Bu(3)SnH source

A number of terminal alkynes were subjected to nickel, cobalt, and molybdenum catalyzed hydrostannations in presence of tributyltin chloride, polymethylhydrosiloxane, potassium fluoride and 18-crown-6 as an situ organotin hydride source to produce vinylstannanes.     

Hydrosilylation of organosilicon acetylenic carbonyl compounds

Conclusions The H₂PtCl₆-catalyzed hydrosilylation of organosilicon acetylenic carbonyl compounds Me₃SiCCCOR (R=H, Me, Ph) with triethylsilane (XH) leads in moderate yield to the formation of the regioisomeric adducts Me₃SiCH=CXCOR and Me₃ SiCX=CHCOR in a 51 mole ratio.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 427–429, February, 1984.     

Reduction of carbonyl compounds via hydrosilylation : I. Hydrosilylation of carbonyl compounds catalyzed by tris(triphenylphosphine)chlororhodium

The hydrosilylation of various carbonyl compounds such as simple aldehydes, simple ketones, α,β-unsaturated carbonyl compounds, α-diketones, acyl cyanides and ketones having an electron-withdrawing group on the α-carbon using tris(triphenylphosphine)chlororhodium as a catalyst is described. Solvolysis of these silyl ethers and silyl enol ethers afforded the corresponding reduced products. The hydrosilylation of α,β-unsaturated carbonyl compounds was found to proceed by 1,4-addition. An oxidative adduct of triethylsilane to the rhodium-(I) complex was obtained as a reaction intermediate. The structure of the adduct was discussed on the basis of its IR and far-IR spectra.     

Catalytic radical addition of carbonyl compounds to alkenes by Mn(II)/Co(II)/O(2) system

The radical addition of enolizable carbonyl compounds such as malonates and malononitrile to alkenes was successfully achieved through a catalytic process using the Mn(II)/Co(II)/O(2) system to afford the corresponding adducts in fair to good yields. Dimethyl malonate added to 1,5-cyclooctadiene to produce a fused bicycle compound.     

Hydrosilylation and double silylation of carbonyl compounds with 1,1′-bis(dimethylsilyl)ferrocene using nickel- and platinum-catalysts

A series of ferrocene-based organosilicon compounds have been prepared via hydrosilylation or double silylation of carbonyl compounds with 1,1′-bis(dimethylsilyl)ferrocene using (C₂H₄)Pt(PPh₃)₂ or Ni(PEt₃)₄ catalysts. In general, while the platinum catalyst (C₂H₄)Pt(PPh₃)₂ preferentially produced cyclic double-silylated products, the Ni(PEt₃)₄ catalyst led to the hydrosilylated ferrocene products from aldehydes or ketones.     

Unusual reaction of beta-hydroxy alpha-diazo carbonyl compounds with Cl3CCN/NaH and Rh(II)-catalyzed reaction of beta-trichloroacetylamino alpha-diazo carbonyl compounds

The hydroxyl group was directly converted into the trichloroacetylamino group by reacting beta-hydroxy alpha-diazo carbonyl compounds with Cl(3)CCN and NaH. Rh(II)-catalyzed reactions of the beta-amino alpha-diazo carbonyl compounds were discussed. [reaction: see text]     

Reductive coupling of allylic acetates with carbonyl compounds by using Pd(0)-SmI2 system

Reductive coupling of allylic acetates with carbonyl compounds proceeded by SmI₂ in the presence of catalytic Pd(0) to yield homoallylic alcohols.     

Silylstannations of alpha,beta-unsaturated carbonyl compounds via the generation of Bu3Sn- in ionic liquids

The tributylstannyl anion, Bu3Sn-, can be generated in imidazolium based ionic liquids from Me3SiSnBu3 and reacted with alpha,beta-unsaturated carbonyl compounds to afford 3-tributylstannylated products in good yields.     

alpha-thiocyanation of carbonyl and beta-dicarbonyl compounds using (dichloroiodo)benzene-lead(II) thiocyanate

The combination reagent (dichloroiodo)benzene and lead(II) thiocyanate in dichloromethane effects oxidation of various enol silyl ethers, ketene silyl acetals, and beta-dicarbonyl compounds, thereby providing an efficient and convenient method for alpha-thiocyanation of carbonyl and beta-dicarbonyl compounds.     

Reverse atom transfer radical polymerisation (RATRP) of methacrylates using copper(I)/pyridinimine catalysts in conjunction with AIBN

N-n-Propyl-2-pyridylmethanimine, 1, N-n-octyl-2-pyridylmethanimine, 2, N-n-lauryl-2-pyridylmethanimine, 3, and N-n-octadecyl-2-pyridylmethanimine, 4 have been used in conjunction with copper(II) bromide and azo initiators for the reverse atom transfer radical polymerisation of a range of methacrylates. AIBN to Cu^IIBr₂ ratios of 0.5:1, 0.75:1 and 1:1 give PMMA with M_n 11 500 g mol⁻¹ (PDi = 1.24) (at 22% conversion), 12 500 g mol⁻¹ (PDi = 1.06) (at 83% conversion) and 10 900 g mol⁻¹ (PDi = 1.11) (at 84% conversion), respectively. A Cu^IIBr₂ complex is demonstrated to be needed at the start of the reaction for good control over molecular weight and polydispersity as reactions using Cu(I)Br as catalyst yielded PMMA of M_n 31 000 g mol⁻¹ (PDi = 2.90), reactions with no copper yield PMMA of M_n 33 000 g mol⁻¹ (PDi = 2.95). The RATRP of styrene was carried out using Cu^IIBr₂ as catalyst. AIBN to Cu^IIBr₂ ratio of 0.5:1, 0.75:1 and 1:1 gave PS with M_n = 12 400 g mol⁻¹ (PDi = 1.27) at low conversion, M_n = 15 500 g mol⁻¹ (PDi = 1.11) and 12 400 g mol⁻¹ (PDi = 1.38), respectively at ∼85% conversion. A series of block copolymers of MMA with BMA, BzMA and DMEAMA (15 600 g mol⁻¹ (PDi = 1.18), 13 300 g mol⁻¹ (PDi = 1.14) 15 300 g mol⁻¹ (PDi) = 1.16), using a PMMA macroinitiator were prepared. Emulsion polymerisation of MMA using [initiator]:[Cu^(II)Br₂] ratio = 0.5:1 with Brij surfactant gave a linear increase of M_n with respect to conversion, final M_n = 112 800 g mol⁻¹ (PDi = 1.42). Further reactions were carried out with [initiator]:[Cu^(II)Br₂] ratio = 0.75:1 and 1:1. Both giving PMMA with M_n ∼ 32 000 g mol⁻¹ (PDi ∼ 2.4). These reactions exhibit no control, this is because the azo initiator is present in excess and all of the monomer is consumed by a free radical polymerisation as opposed to a controlled reaction. Particle size analysis (DLS) showed the particle size between 160 and170 nm in all cases.     

Highly chemoselective reductive amination of carbonyl compounds promoted by InCl3/Et3SiH/MeOH system

A new strategy has been developed for reductive amination of aldehydes and ketones with the InCl3/Et3SiH/MeOH system, which is a nontoxic system with highly chemoselective and nonwater sensitive properties. The methodology can be applied to a variety of cyclic, acyclic, aromatic, and aliphatic amines. Functionalities including ester, hydroxyl, carboxylic acid, and olefin are found to be stable under our conditions. The reaction shows a first-order kinetics profile with respect to both InCl3 and Et3SiH. Spectroscopic techniques such as NMR and ESI-MS have been employed to probe the active and resulting species arising from InCl3 and Et3SiH in MeOH, which are important in deriving a mechanistic proposal. In the ESI-MS studies, we have first discovered the existence of stable methanol-coordinated indium(III) species which are presumably responsible for the gentle generation of indium hydride at room temperature. The solvent attribution was crucial in tuning the reactivity of [In-H] species, leading to the establishment of mild reaction conditions. The system is superior in flexible tuning of hydride reactivity, resulting in the system being highly chemoselective.     

Direct reductive amination of carbonyl compounds using bis(triphenylphosphine) copper(I) tetrahydroborate

A direct reductive amination protocol for aldehydes/ketones using bis(triphenylphosphine) copper(I) tetrahydroborate as a novel reducing agent in the presence of sulfamic acid has been developed. The reagent chemoselectively reduces the imine moiety and does not affect other reducible functionalities such as chloro, nitro, cyano and methoxy.     

Expeditious oxidation of alcohols to carbonyl compounds using iron(III) nitrate

An efficient and solvent-free protocol for the oxidation of alcohols to corresponding carbonyl compounds using iron(III) nitrate nonahydrate has been developed.     

3-dinitrobenzoylhydrazones of organosilicon carbonyl compounds

Conclusions The reaction of 3,5-dinitrobenzoylhydrazide with organosilicon aldehydes and ketones was investigated. It was shown that this reagent forms readily crystallizing 3,5-dinitrobenzoylhydrazones and is suitable for the identification of organosilicon carbonyl compounds.     

Reduction and coupling reaction of carbonyl compounds by KI/Fe(OH)3 in aqueous media

ABSTRACT

A small amount of ferric hydroxide was found to catalyze KI-activated coupling of aromatic aldehydes and acetophenone to give the corresponding pinacols in high yields. The ratio of meso to dl isomer was approximately 1:1. Most aliphatic aldehydes and ketones were unreactive under the same conditions.     

Indium-catalyzed allylation of carbonyl compounds with the Mn/TMSCl system

Allylation of aldehydes and ketones with allyl bromide was performed with a catalytic amount of indium powder (from 0.01 to 0.1 equiv.) in THF in the presence of manganese and trimethylsilyl chloride as the reducing and oxophilic agent, respectively.     

Evaluation of a new linker system cleaved using samarium(II) iodide. Application in the solid phase synthesis of carbonyl compounds

A new linker design for solid phase synthesis has been developed that is cleaved under mild, neutral conditions using samarium(II) iodide. The feasibility of the linker approach has been illustrated in the solid phase synthesis of ketones and amides using an oxygen linker. Insights into the mechanism of the samarium(II) iodide cleavage reaction are described and the potential of a sequential cleavage carbon-carbon bond forming process is assessed.     

Vinylogous nitroaldol (Henry) reaction using 3,5-diethyl-4-nitroisoxazole and carbonyl compounds

3,5-Diethyl-4-nitroisoxazole reacted with carbonyl compounds in the presence of an amine catalyst. The vinylogous nitroaldol adducts were isolated in good yields.     

Reductive etherification of carbonyl compounds with alkyl trimethylsilylethers using polymethylhydrosiloxane (PMHS) and catalytic B(C6F5)3

A facile synthesis of symmetrical and unsymmetrical ethers is achieved by reductive coupling of carbonyl compounds with alkoxysilanes. This reaction is performed using inert polymethylhydrosiloxane as the hydride source and B(C₆F₅)₃ as the catalytic activator of the PMHS.