Csp3-csp3 homocoupling reaction of benzyl halides catalyzed by rhodium.

A highly reactive alkylrhodium complex was formed from Me(2)Zn and RhCl(PPh(3))(3) and effectively catalyzed a Csp(3)-Csp(3) homocoupling reaction of benzyl halides. A Csp(3)-Csp(3) coupling reaction using Rh catalyst has not been reported up to now. The reaction proceeded under very mild conditions and gave the corresponding homocoupling products even if they had reactive substituents such as an uncovered formyl or hydroxymethyl group.

Mechanistic studies on alpha-trifluoromethylation of ketones via silyl enol ethers and its application to other carbonyl compounds.

Synthesis of alpha-CF(3) carbonyl compounds has been recognized to be difficult up to now because the polarization of CF(3)(delta-)-I(delta+) is opposite to that of CH(3)(delta+)-I(delta-), and this makes it difficult to introduce CF(3)(+) unit to enolates. We recently reported an effective alpha-trifluoromethylation of ketones by using Et(2)Zn with Rh catalyst, but the mechanism has not fully been cleared. Now, we carried out the detailed mechanistic studies and found the involvement of a highly reactive alkylrhodium complex which derived from Et(2)Zn and RhCl(PPh(3))(3) in this alpha-trifluoromethylation.

Synthesis of recyclable fluorous chiral ligands and evaluation of their catalytic activity toward asymmetric addition of dimethylzinc to aldehydes.

The asymmetric addition of Me(2)Zn to aldehydes is very slow and mostly gives low ee values. Previously, we reported the synthesis of a fluorous chiral ligand, (4R,5S,alpha'R)-2,2-dimethyl-alpha,alpha,alpha'-tris(perfluorooctyl)-2,3-dioxolane-4,5-dimethanol (1 a), derived from tartarate as a chiral pool. Ligand 1 a showed high activity toward the addition of Me(2)Zn to aldehydes with high enantiomeric excess.

Direct synthesis of 1,3-diketones by Rh-catalyzed reductive alpha-acylation of enones.

1,3-Diketones were synthesized from alpha,beta-unsaturated ketones by treatment with acid chlorides and Et(2)Zn in the presence of RhCl(PPh(3))3. This is a very simple and extremely chemoselective reaction to give the adduct at the alpha-position of alpha,beta-unsaturated ketones.

A redox-silent analogue of tocotrienol inhibits hypoxic adaptation of lung cancer cells.

We have previously reported that a redox-silent analogue of alpha-tocotrienol (T3), 6-O-carboxypropyl-alpha-tocotrienol (T3E) shows more potential anti-carcinogenic property than T3 in a lung cancer cell (A549 cell). However, the mechanisms by which T3E exerts its potential anti-carcinogenic effect is still unclear. As tumor malignancy is associated with hypoxia adaptation, in this study, we examined whether T3E could suppress survival and invasion in A549 cells under hypoxia.

Formation of quaternary carbon center with a trifluoromethyl group using a Pd-catalyzed allylation reaction.

Synthesis of compounds with quaternary carbons is one of the most attractive reactions in the synthetic chemistry. However, there are only a few reports on synthesis of the compounds with a fluoroalkyl group at a quaternary carbon center. Recently, we reported the synthesis of alpha-trifluoromethylated ketones by the reaction of alpha,beta-unsaturated ketones with CF(3)-I using a Rh catalyst.

Synthesis of a fluorous ligand and its application for asymmetric addition of dimethylzinc to aldehydes.

A new fluorous ligand was synthesized from the acetonide of dimethyl tartarate, which showed excellent asymmetric induction on the addition of dimethylzinc to aldehydes. This ligand will be useful for synthesis of bioactive compounds with a methyl carbinol moiety. It could be recycled without using a fluorous solvent or a fluorous column.

[Synthesis of fluorine compounds based on special properties of fluorine compounds].

This review describes new syntheses of organofluorine compounds taking advantage of the special properties of fluorine compounds as synthones. The main reactions presented are as follows: 1) Trifluoromethylation of aryl or alkyl halides. Application of this reaction for the synthesis of fluorine analogues of nucleic acid bases is discussed.

Induction of cytotoxicity in human lung adenocarcinoma cells by 6-O-carboxypropyl-alpha-tocotrienol, a redox-silent derivative of alpha-tocotrienol.

Tocotrienols are one of the most potent anticancer agents of all natural compounds and the anticancer property may be related to the inactivation of Ras family molecules. The anticancer potential of tocotrienols, however, is weakened due to its short elimination half life in vivo. To overcome the disadvantage and reinforce the anticancer activity in tocotrienols, we synthesized a redox-silent analogue of alpha-tocotrienol (T3), 6-O-carboxypropyl-alpha-tocotrienol (T3E).

Rhodium-catalyzed novel trifluoromethylation at the alpha-position of alpha,beta-unsaturated ketones.

Treatment of alpha,beta-unsaturated ketones with CF(3)I in the presence of Et(2)Zn and RhCl(PPh(3))(3) gave novel alpha-trifluoromethylation products in good yields. Hydrogen transfer from the ethyl group on the rhodium complex to the beta-position of the enone seems to play an important role in this reaction.

alpha-Tocopheryloxybutyric acid enhances necrotic cell death in breast cancer cells treated with chemotherapy agent.

The overexpression of HER-2 receptor contributes to malignant transformation of breast cancer cells. We have reported that alpha-tocopheryloxybutyric acid (TE), non-antioxidative vitamin E ether derivative inhibits the activation of HER-2 receptor. The present study was undertaken to estimate if TE could act as a useful anti-cancer agent against a breast cancer cell overexpressing HER-2 receptor (MDA-MB-453 cell line) in combination with a conventional chemotherapy agent, adriamycin (ADR).

New approach to a novel axially chiral ligand showing spontaneous enrichment of axial chirality.

We have synthesized novel axially chiral ligand with two chiral centers, (R)-(R)(2)- and (S)-(S)(2)-2,2'-bis(2,2,2-trifluoro-1-hydroxyethyl)biphenyl (1), which showed a high asymmetric induction when used as ligand. Here, another new approach to 1 by kinetic and thermodynamic resolution is presented which gave these ligands in a much shorter steps, in a higher yield, and in a higher enantiomeric excess.