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Direct catalytic transformation of chlorosilanes into organosilicon compounds remains challenging due to difficulty in cleaving the strong Si-Cl bond(s). We herein report the palladium-catalyzed cross-coupling reaction of chlorosilanes with organoaluminum reagents. A combination of [Pd(C

The transition-metal-catalysed hydrosilylation reaction of alkenes is one of the most important catalytic reactions in the silicon industry. In this field, intensive studies have been thus far performed in the development of base-metal catalysts due to increased emphasis on environmental sustainability. However, one big drawback remains to be overcome in this field: the limited functional group compatibility of the currently available Pt hydrosilylation catalysts in the silicon industry. This is a serious issue in the production of trichloro(3-chloropropyl)silane, which is industrially synthesized on the order of several thousand tons per year as a key intermediate to access various silane coupling agents. In the present study, an efficient hydrosilylation reaction of allyl chloride with trichlorosilane is achieved using the Rh(I) catalyst [RhCl(dppbzF)]2 (dppbzF = 1,2-bis(diphenylphosphino)-3,4,5,6-tetrafluorobenzene) to selectively form trichloro(3-chloropropyl)silane. The catalyst enables drastically improved efficiency (turnover number, TON, 140,000) and selectivity (>99%) to be achieved compared to conventional Pt catalysts. Hydrosilylation of allyl chloride with trichlorosilane is industrially important but often proceeds unselectively. Here a Rh(I) catalyst which achieves 99% selectivity on gram scale is described, based on bidentate phosphine ligands.

A nickel complex/Lewis acid combination effectively catalyzed the direct silyl-Heck reaction of chlorosilanes, which are key raw materials in the organosilicon industry, to give synthetically important alkenylsilane products. Trichlorosilanes, dichlorosilanes, and monochlorosilanes underwent the silyl-Heck reaction to afford the corresponding alkenylsilanes in high yields. In the reactions of dichlorosilanes, a single substitution occurred to give monoalkenylsilanes in a highly selective manner.

Asymmetric diboration of N -acyl-protected allylamines such as substituted imides, amides, and carbamates catalyzed by chiral rhodium[bis(oxazolinyl)phenyl] complexes followed by oxidation in one-pot was realized to produce optically active 3-amino-1,2-propanediol derivatives in high enantioselectivities up to 99%.

Hydrosilylation of alkenes is an important reaction for the production of organosilicon compounds such as industrially important silicones and silane coupling agents. To synthesize highly sophisticated organosilicon materials, it is of great importance to develop novel hydrosilylation catalysts with good compatibility towards a wide range of functional groups. This review highlights the main advances made in this area. Efforts to develop Pt catalysis systems as well as environmentally benign base-metal catalyst systems have been collected with the aim of providing a comprehensive overview of the subject from the viewpoint of both academia and industry.

Reactions of allyl-functionalized poly(ethylene glycol) (PEG) derivatives with alkoxysilanes proceeded efficiently to furnish the corresponding hydrosilylated products in good to excellent yields using a ruthenium catalyst, [RuCl2(nbd)]n. A preliminary mechanistic study supported the pivotal role of the PEG moiety, which coordinated to the ruthenium atom during the reaction to achieve high reaction selectivity. This method may be applicable to the synthesis of various PEGs with a silyl terminus, which is useful as biocompatible and low toxic silane coupling agents.

In the field of asymmetric synthesis, the development of new chiral ligands has been regarded as an attractive challenge for decades. Novel chiral ligands can often have a great impact on synthetic protocols. In this context, we are currently interested in the application of 1,10-phenanthroline (phen) as an entirely new class of chiral ligand. To handle this issue, we designed a chiral phen ligand that provides the N,N,O-tridentate coordination of the phen moiety and an additional phenolic hydroxyl group. As phen possesses greater coordination ability with various ions, our chiral phen ligand would be valuable as one of the "privileged" chiral ligands applied to a broad range of metal catalysts and new reactions. This account summarizes the results of the application of the chiral phen ligand to various kinds of metal catalysis.

Chiral aluminum Lewis acid catalyst composed of Me(3)Al and 3,3'-bis(trimethylsilyl)-BINOL in a 2:1 ratio was found to promote novel catalytic asymmetric ring expansion of cyclohexanone with α-substituted α-diazoacetates to give seven-membered rings with an all-carbon quaternary center. Application of this strategy to 4-substituted cyclohexanones opened up a novel way for the catalytic desymmetrizing asymmetric construction of cycloheptanones bearing remote α,δ-chiral centers.

In the presence of a Cu(II) complex of axially chiral, N,N,O-tridentate phenanthroline ligand (S)-2, asymmetric oxygen atom transfer of oxindole derivatives (3) using Davis’ oxaziridine (4) occurred to give the corresponding 3-aryl-3-hydroxy-2-oxindole derivatives (1) with excellent enantioselectivity (up to 96% ee). The X-ray crystallographic analysis of the isolated Cu(II) complex disclosed its N,N,O-tridentate coordination, which is critical to realize effective catalytic activity.

[Structure: see text] A new Brønsted acid-assisted chiral Brønsted (chiral BBA) acid catalyst (1) was developed by substituting a hydroxy group of optically active 1,1'-bi(2-naphthol) with a stronger Brønsted acidic group such as a bis(trifluoromethanesulfonyl)methyl group. The enantioselective Mannich-type reaction of ketene silyl acetals with aldimines catalyzed by (R)-1 in the presence of stoichiometric achiral proton sources gave (S)-beta-amino esters in high yield with moderate to good enantiomeric excesses.

Insertion of one methylene unit into the C-C bond of cyclohexanones is a potentially useful, straightforward method for the construction of seven-membered carbocycles. An especially appealing but largely unexplored method in this arena is the nucleophilic addition of diazoalkanes to the Lewis acid-activated cyclohexanones and subsequent ring expansion accompanied by the extrusion of nitrogen (direct Tiffeneau-Demjanov-type ring expansion). Our primary finding is the unprecedented insertion of alpha-alkyldiazoacetates to cyclohexanone and its heteroanalogues, generating seven-membered rings with one all-carbon quaternary center. On the basis of this finding, highly diastereoselective ring expansion of substituted cyclohexanones was developed, furnishing seven-membered rings with 1,4-quaternary-tertiary, 1,4-quaternary-quaternary, or 1,3,5-quaternary-tertiary-tertiary stereogenic centers in a single operation starting from readily available materials. The stereochemical outcome of the product can be easily predicted from the conformation of starting cyclohexanones. Enantioenriched products could be also accessed by the use of (-)-phenylmenthyl alpha-alkyldiazoacetates.

Asymmetric redox C-C bond formation between alpha-alkyl-alpha-diazocarbonyl compounds and aldehydes was developed as a practical and general method for the construction of alpha-alkyl-beta-keto imides having a chiral nonracemic tertiary stereogenic center.

Aryldiazoacetates could be formally inserted into the carbon−carbon bond of the Bronsted acid-activated aromatic and α,β-unsaturated aldehydes. Use of phenylmenthyl esters allowed the asymmetric induction at the inserted all-carbon quaternary carbon center with the excellent stereoselectivities.