Synthesis of Novel Pseudo-Enantiomeric Phase-Transfer Catalysts from Cinchona Alkaloids and Application to the Hydrolytic Dynamic Kinetic Resolution of Racemic 3-Phenyl-2-oxetanone.

Naturally occurring Cinchona alkaloids such as quinidine (QD)/cinchonine (CN) and their diastereomers, quinine (QN)/cinchonidine (CD), have been recognized as pseudo-enantiomeric pairs. Utilizing these pseudo-enantiomeric alkaloids as chiral resources provides complementary enantioselectivity in many asymmetric reactions. During the screening of Cinchona alkaloid phase-transfer catalysts (PTCs) in the hydrolytic dynamic kinetic resolution of racemic 3-phenyl-2-oxetanone (1) to tropic acid (2), we found that the introduction of a 4-trifluoromethylphenyl group at the vinyl terminus of BnQN significantly reduced the enantioselectivity to 41% enantiomeric excess (ee).

Hydrolytic dynamic kinetic resolution of racemic 3-phenyl-2-oxetanone to chiral tropic acid.

Tropic acid was synthesized in a good yield and with high enantioselectivity (81% ee) under non-biphasic conditions the novel hydrolytic dynamic kinetic resolution of racemic 3-phenyl-2-oxetanone (tropic acid β-lactone) in the presence of a chiral quaternary ammonium phase-transfer catalyst and strongly basic anion exchange resin as the hydroxide ion donor.

Efficient synthesis of 3-arylphthalides using palladium-catalyzed arylation of aldehydes with organoboronic acids.

The synthesis of 3-arylphthalides via palladium-catalyzed arylation of aldehydes with organoboronic acids was achieved using the thioether-imidazolinium carbene ligand in good to excellent yields and was carried out using 1.0 mol % of the catalyst with high substrate tolerance.

Palladium-catalyzed 1,2-addition of potassium aryl- and alkenyltrifluoroborates to aldehydes using thioether-imidazolinium carbene ligands.

Palladium-catalyzed 1,2-addition of potassium aryl- and alkenyltrifluoroborates to aldehydes using thioether-imidazolinium carbene ligands proceeded readily under aqueous conditions. This process tolerated a diverse range of potassium trifluoroborate salts and aldehydes, giving a variety of carbinol derivatives with good to excellent yields.

Design and synthesis of N-alkyl oxindolylidene acetic acids as a new class of potent Cdc25A inhibitors.

The oxindolylidene acetic acids having long N-alkyl chains exhibited strong inhibitory activity toward dual specificity phosphatase Cdc25A.

Efficient 1,2-addition of aryl- and alkenylboronic acids to aldehydes catalyzed by the palladium/thioether-imidazolinium chloride system.

The high level of catalyst performance was attainable in the palladium-catalyzed 1,2-addition of aryl-, heteroaryl-, and alkenylboronic acids to aromatic, heteroaromatic, and aliphatic aldehydes using thioether-imidazolinium chloride L5 as a heterobidentate carbene ligand precursor.

Design and synthesis of novel C2-symmetric chiral piperazines and an application to asymmetric acylation of sigma-symmetric 1,2-diols.

[Structure: see text] A novel alicyclic chiral C2-symmetric piperazine, (S,S)-7, is designed and synthesized from L-proline. Benzoylation of a series of cyclic and acyclic meso-1,2-diols with a catalytic amount of (S,S)-7 and CuCl2 provided optically active monobenzoates with high enantioselectivity.

Design and synthesis of novel Cdc25A-inhibitors having phosphate group as a hydrophilic residue.

Compounds (6a-e) were synthesized by phosphorylation of hydrophobic perhydroindan derivatives derived from vitamin D(3), and were found to show strong inhibitory activity towards dual-specificity phosphatase Cdc25A (IC(50)=0.7-24.5 microM).

Diastereoselective synthesis of D- and L-myo-inositol 3,4,5,6-tetrakisphosphates from D-glucose via dihydroxylation of (+)-conduritol B derivatives.

Syntheses of D- and L-myo-inositol 3,4,5,6-tetrakisphosphates were achieved via diastereoselective 1,2-addition of vinylcopper reagent with the chiral aldehyde prepared from 1,2,5,6-diisopropylidene-D-glucose, ring-closing metathesis of 1,7-diene with Grubbs catalyst followed by catalytic OsO(4) dihydroxylation of (+)-conduritol B derivatives.

Design and synthesis of dysidiolide analogs from vitamin D3: novel class of Cdc25A inhibitors.

Potent dysidiolide analogs were synthesized by structural hybridization of dysidiolide and vitamin D(3). These analogs exhibited strong inhibitory activity toward dual-specificity phosphatase Cdc25A (IC(50)=0.44-0.