Shoji Wakabayashi

A new synthetic method for γ-butyrolactols by the paladium-catalyzed regioselective oxidation of 1-alken-4-ols

Abstract 3-Substituted 1-alken-4-ols were oxidized with PdCl 2 -benzoquinone regioselectively at the terminal carbon to afford cyclic hemiacetals (γ-butyrolactols), which were converted to γ-butyrolactones by the Jones oxidation. This reaction was applied to the syntheses of optically active deoxyribose and γ-butenolides.

Intramolecular Sm2+ and Sm3+ promoted reaction of γ-oxy-δ-ketoaldehyde; stereocontrolled formation of pinacol and lactone

Abstract Samarium promoted intramolecular pinacol coupling and Tishchenko oxidoreduction of γ-oxy-δ-ketoaldehyde proceeded stereospecifically. Newly forming hydroxy group is oriented anti to γ-silyoxy group in both reactions.

Synthesis of optically active 4-hydroxyalk-2-enenitriles; Reaction of optically active 2-(p-chlorophenylsulfinyl)acetonitrile with aldehydes in the presence of piperidine in acetonitrile

Abstract Reaction of optically active 2-(p-chlorophenylsulfinyl)acetonitrile ((R)- 1a ) with aldehydes, in the presence of piperidine in acetonitrile at r.t., gave optically active 4-hydroxyalk-2-enenitriles in good optical and chemical yields. The absolute configuration of (−)-4-hydroxypent-2-enenitrile, predominantly obtained by the reaction of (R)- 1a with propanal, was determined to be R.

Preparation of 4-hydroxy-2-alkenenitriles from phrnylsulfinylacetonitrile with keetones or aldehydes, and its synthetic application to substituted furans

Abstract The reaction of phenylsulfinylacetonitrile 1 with ketones or aldehydes gave 4-hydroxy-2-alkenenitriles which were converted to 2- and/or 3-substituted furans by the treatment with diisobutylaluminumhydride(DIBAL) followed by acid hydrolysis.

Facile formation of 4-hydroxyalk-2-enone functionality

Reaction of aldehyde with 1-(phenylsulfinyl)alkan-2-one (1), in the presence of diethylamine (and acetic acid) in acetonitrile at 60 °C, gave 4-hydroxyalk-2-enone derivative in good yield.

Ipso substitution of 2-alkylsulfinylpyridine by 2-pyridyllithium; a new preparation of oligopyridine and their bromomethyl derivatives

Abstract Unsymmetrical and symmetrical 2,2′-bipyridines 5 and 6 have been prepared. The methods applied are new and offer efficient syntheses of higher oligopyridines and their bromomethyl derivatives.

Syntheses of PGJ2 type analogues: 16-hydroxy-11-oxo-Δ5,9,12,14-prostatetraenoic acid t-butyl ester and its related derivatives

PGJ2 analogues, the title compound (8c) and its related derivatives (8a, 8b), were synthesized via the three-component coupling process involving 1,4-addition reaction of phenylsulfinylallylic carbanion (2′) to cyclopentenone derivative (1) followed by trapping the generated enolate with aldehyde (3).

Ligand coupling through σ-sulfurane — complete retention of geometric configuration of allylic and vinylic groups in the reactions of allylic and vinylic sulfoxides with Grignard reagents

Abstract The reaction of p-benzenesulfonylphenyl crotyl sulfoxide with Grignard reagents is considered to proceed via formation of an incipient σ-sulfurane to afford the coupling product, p-benzenesulfonyl-crotylbenzene, in which the geometric configuration of crotyl group was completely preserved. No rearrangement was observed in the coupling reaction of p-benzenesulfonylphenyl α-methylallyl sulfoxide. Such a complete retention of geometric configuration was also found in the reactions of 2-pyridyl and p-benzenesulfonylphenyl styryl sulfoxides with Grignard reagents.

New synthetic reaction by electrolysis. III. α-acetoxylation of sulfide☆

Abstract Sulfides are directly converted effectively to the corresponding α-acetoxy sulfides by electrolysis in acetic acid.

Sensitive nature of ligand coupling and pseudorotation to electronic effect of substituent---ligand coupling in the reactions of benzylic aryl sulfoxides with benzylic Grignard reagents☆

Abstract Unlike the reaction of benzylic 2-pyridyl sulfoxides with benzylic Grignard reagents, in the reaction of p-benzenesulfonylphenyl benzylic sulfoxides with benzylic Grignard reagents, benzylic groups bearing an electron-withdrawing group tends to couple with the aryl group preferentially. This change is considered to be due to a slight change of electronic environements which would effect on the ease of pseudorotation2) of the incipient σ-sulfurane formed during the reaction.