| Research Abstract |
The following results are obtained in this research project
1.New Reactivity of a Reducing Reagent Generated from a Copper(I) Salt and a Hydrosilane : Selective Reduction of Ketones and Olefins Conjugated with an Aromatic Group
Aromatic ketones and olefins were selectively converted to the corresponding alcohols and alkanes by a reagent prepared from a copper(I) salt and a hydrosilane. Excess use of the hydrosilane is most important to attain the high reactivities. One-electron transfer process as well as nucleophilic reaction of hydride would contribute the selectivity
2.First Gold Complex-catalysed Selective Hydrosilylation of Organic Compounds
The first example of the hydrosilylation of organic compounds such as aldehydes and an aldimine using a catalytic amount of a gold complex, which accomplished versatile regio-and chemoselective reduction of carbonyl compounds, is described
3.Convenient Methods for Conjugate Silylation of α,β-Enones Using a Disilane Mediated by a Copper(I) Salt
The β
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-Silylation of α,β-enones using disilanes smoothly proceeds with a stoichiometric and catalytic amount of a readily available copper(I) salt by easy manipulation. At elevated temperature, a stoichiometric amount of CuCl is effective for the silylation. In the presence of a silyl triflate, use of a catalytic amount of Cu_2O affords the product even at lower temperature. These procedures offer convenient tools for the synthesis of b-silylated ketones.
4.New Method for Introduction of a Silyl Group into α,β-Enones Using a Disilane Catalyzed by a Copper(I) Salt
This paper describes that the reaction of a disilane with a Cu(I) salt efficiently induces cleavage of the Si-Si bond cc generate a silyl nucleophile in an aprotic polar solvent and its 1,4-addition to a,(3-unsaturated enones smoothly proceed' with a catalytic amount of a Cu(I) salt. 1,1,2,2-Tetramethyl-l,2-diphenyldisilane reacts with (CuOTf)_2◇C_6H_6 to give 1,1,2,2-tetramethyl-1,2-diphenyldisiloxane at room temperature in DMI. In the presence of a,b-enones, the conjugate silylation smoothly proceeds to give the corresponding 3-silylated product in good yields (up to 100%) even with 5 mol% (10 mol% for Cu(I)) of (CuOTf)_2◇C_6H_6 and tributylphosphine (11 mol%) in DMF, DMI and diglyme. This reaction is successfully applied to hexamethyldisilane to generate a trimethylsilyl nucleophile, hitherto not easily accessible. A plausible reaction mechanism via the regeneration of CuOTf in a catalytic cycle is proposed
5.Boration of an α,β-enone using a diboron promoted by a copper(I)-phosphine mixture catalyst
The Cu(I)-catalyzed boration of an a,(3-enone using a diboron is described. Combination of a Cu(I) salt and tributylphosphine is an effective catalyst system, though the individual use of Cu(I) and tributylphosphine is not active far the reaction
6.An Unprecedented Catalytic Reaction Using Gold(I) Complexes
This paper describes that Au complexes efficiently catalyze dehydrogenative dimerization of trialkylstannanes and its catalytic activity is extensively high (0.1 mol%, 48 h) as comparable to the Pd catalysts Less
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