Kazutaka Arai

A highly efficient synthesis of optically pure γ-iodo allylic alcohols and their conversion into various optically active allylic alcohols

Abstract Kinetic resolution of γ-iodo allylic alcohols 1 by the Sharpless asymmetric epoxidation reaction proceeds with very large rate differences for the two enantiomers, thus providing a highly efficient method for preparation of optically pure 1 . The alcohols 1 thus prepared can be readily converted into various secondary allylic alcohols through the coupling reaction with nucleophiles.

Synthesis of corey lactone via highly stereoselective asymmetric Diels-Alder reaction

Abstract We have succeeded in a highly stereoselective asymmetric Diels-Alder reaction between a chiral acrylate 3a derived from commercially available D-pantolactone 2 and 5-benzyloxymethyl-cyclopentadiene 4 to give the adduct 5a in 94% d.e. and 79% yield for the synthesis of Corey lactone 1 .

Short-step synthesis of naproxen. Regioselective Friedel-Crafts reaction of 2-chloro-2-alkylthio-propionates

Abstract 2-(6-Methoxy-2-naphthyl)propionic acid ( 4 ), dl-naproxen, was conveniently prepared by the regioselective reaction of alkyl 2-chloro-2-alkylthio-propionate ( 2 ) and 2-methoxynaphthalene ( 1 ) in good yield. This Friedel-Crafts reaction was found to be applicable to the other electron-rich aromatics.

A new synthetic route of corey lactone having ω-side chain

Corey lactone having ω-side chain 1a is an important intermediate for syntheses of prostaglandins. Now we have succeeded in developing a new synthetic route of 1a from methylenecyclopentanone having ω-side chain 2a. The new synthetic route has two crucial steps as follows. 1) Hydroxymethyl unit introduction by using organozinc reagent. 2) Oxidation of diol to lactone by using N-oxoammonium salt in combination with sodium bromite.