Hidetoshi Kitagawa

Remote asymmetric induction for chiral 1,4-diols using a chiral acetal derived from chiral hydrobenzoin

Abstract A new route to chiral 1,4-diols has been developed in a 4 step sequence from the ene acetal, prepared from 4-pentenal and chiral hydrobenzoin, involving a remote asymmetric induction as a key step.

Asymmetric Desymmetrization of Saturated and Unsaturated meso-1,2-Diols

Abstract An asymmetric desymmetrization of saturated and unsaturated cyclic and acyclic meso-1,2-diols has been developed from the ene acetals, prepared from the norbornene carboxyaldehyde and meso-1,2-diols. The intramolecular haloetherification of the ene acetals as a key step afforded 8-membered acetals in a stereoselective manner just by the reaction of norbornene olefin even when the ene acetals from unsaturated meso-1,2-diols having olefins in the same molecule were used. Subsequent reductive elimination, followed by protecting the hydroxy group and transacetalization, gave optically active 1,2-diol derivatives and the starting ene acetals in good yields.

Asymmetric synthesis using C2-symmetric diols: Use of (5R,6R)-3-acetoxy-5,6-diphenyl-1,4-dioxan-2-one as a chiral synthetic equivalent of 1,2-ethanediol 1,2-dicarbocation

Abstract A new route to chiral diol systems has been developed based on double nucleophilic addition to the cationic ions fixed on a 6-membered ring system using chiral hydrobenzoin as an auxiliary.

DESYMMETRIZATION OF UNSATURATED MESO-1,2-DIOLS VIA AN INTRAMOLECULAR HALOETHERIFICATION OF ENE ACETALS : A REMARKABLE KINETIC CONTROL

Abstract Haloetherification reaction of the chiral ene acetals derived from unsaturated meso -1,2-diols and chiral non-racemic norbornene aldehyde proceeded in an intramolecular manner with an unexpectedly high kinetic control. This method has been successfully employed for the desymmetrization of unsaturated meso -1,2-diols leading to their optically pure derivatives.

Diastereotopic group selective intramolecular conjugate addition of 4-(2-hydroxyethyl)-p-quinol derivatives: Synthesis of the optically pure cis-7-oxabicyclo[4.3.0]non-2-en-4-one skeleton

Abstract Diastereotopic group selective cyclizadon of 4-(2-hydroxyethyl)-p-quinol derivatives was achieved and the reaction applied to the synthesis of the optically pure cis-7-oxabicyclo[4.3.0]non-2-en-4-one skeleton.

Direct regioselective formation of polysubstituted tetrahydrofurans from umprotected polyols

The reaction of unprotected polyols (tetraols, pentitol and hexitol) with trimethyl orthobenzoate in CH 2 Cl 2 -MeOH afforded polysubstituted tetrahydrofurans in a one-pot synthesis

Reaction of diols and triols with trialkyl orthoesters: facile one-pot formation of oxacyclic compounds from triols

Reaction of diols and triols with trialkyl orthoesters was studied and facile one-pot formation of oxacyclic compound from triols was developed

Organic synthesis utilizing Beckmann fragmentation: highly stereoselective C–C bond formation in the reaction of 2,3-isopropylidenedioxycyclohexanone oxime esters with organoaluminium reagents

Highly Stereoselective C–C bond formation occurred in the reaction of 2,3-isopropylidenedioxycycfohexanone oxime esters with organoaluminium reagents and the reaction was applied to the syntheses of (±)-endo-brevicomin and the synthetic intermediate of (±)-juvenile hormone.