Katsumasa Nonoshita

Unusual conjugate addition of organolithium reagent to α, β-unsaturated ketone

Abstract The conjugate addition of organolithium reagent to α, β-unsaturated ketone has been accomplished with methylaluminum bis(2, 6-di- tert -butyl-4-alkylphenoxide) (MAD and MAT). Here combination of alkyllithium and MAD (or MAT) constitutes an amphiphilic system that allows to exhibit unusual selectivity in the alkylation of enones with alkyllithium.

Organoaluminum-promoted Claisen rearrangement of bisallyl vinyl ethers

Abstract The Claisen rearrangement of bisallyl vinyl ethers with exceptionally bulky organoaluminum reagents exhibits unprecedented regiochemical control not observable in the ordinary thermal rearrangement.

Electronic and Steric Effects of Lewis Acidic Organoaluminum Reagents in the Diels-Alder Reaction

Abstract The influence of electronic and steric effects of modified organoaluminum reagents to the stereoselectivity in the Diels-Alder and hetero-Diels-Alder reactions has been examined.

STEREOSELECTIVE SYNTHESIS OF J-104,118 AND J-104,123, NOVEL, POTENT INHIBITORS OF SQUALENE SYNTHASE

Abstract A novel class of squalene synthase inhibitors (J-104,118 and J-104,123) were synthesized efficiently. An amine intermediate 1 was synthesized using two distinct methods. First, the racemic amine 1 was synthesized diastereoselectively using a key reaction consisting of the stereo-controlled reduction of the ketone 7 by L-Selectride®. Second, the optically active amine 1 was synthesized efficiently and enantioselectively using Sharpless dihydroxylation as a key reaction. A stereo-controlled method for synthesizing J-104,123 was developed starting from a commercially available methyl ( R )-3-hydroxybutyrate.

Efficient and stereoselective synthesis of J-104,118, a novel, potent inhibitor of squalene synthase

J-104,118, a novel and potent inhibitor of squalene synthase, was synthesized stereoselectively. The chiral amine 1 was efficiently synthesized by Sharpless asymmetric dihydroxylation as a key reaction.