Makoto Hojo

Palladium catalyzed oxycarbonylation of 4-penten-1,3-diols: efficient stereoselective synthesis of cis 3-hydroxytetrahydrofuran 2-acetic acid lactones

Abstract cis 3-Hydroxytetrahydrofuran acetic acid lactones have been prepared selectively and in high yield by an intramolecular palladium catalyzed oxycarbonylation of 4-penten-1,3-diols under mild conditions (room temperature, 1 atm of CO).

Inter- and intramolecular di-alkoxycarbonylation of 3-butenols catalyzed by palladium(II)

Abstract Palladium(II) salt catalyzes the inter- and intramolecular di-alkoxycarbonylation of 3-butenols to provide γ-butyrolactone 2-acetic acid esters under 1 atm of carbon monoxide.

Synthesis of 2-vinyl-γ-butyrolactones by the palladium-catalyzed decarboxylative carbonylation of 3-vinyl-1-oxo-2,6-dioxacyclohexanes

Abstract 3-Vinyl-1-oxo-2,6-dioxacyclohexanes undergo a decarboxylative carbonylation by a catalysis of Pd(0) to give 2-vinyl-γ-butyrolactones in high yield (typically in the presence of 3 mol% of Pd(PPh 3 ) 4 in dioxane at room temperature under 1 atm of CO).

Synthesis of 6-alkoxy-3-aryl-6-trimethylsilyloxy-5,6-dihydro-4H-1,2-oxazines and their acid-catalysed hydrolysis leading to 3-aryl-5,6-dihydro-4H-1,2-oxazin-6-ones and/or 4-aryl-4-(hydroxyimino)butyric acid esters

The cycloaddition of α-nitrosostyrene and its ring-substituted derivatives, which are generated by the reaction of α-chloroacetophenone oxime and its ring-substituted derivatives with K2CO3 in tetrahydrofuran, with ketene trimethylsilyl acetals proceeds to afford 6-alkoxy-3-aryl-6-trimethylsilyloxy-5,6-dihydro-4H-1,2-oxazines. These oxazines are susceptible to hydrochloric acid-catalysed hydrolysis affording 3-aryl -5,6-dihydro-4H-1,2-oxazin-6-one and/or 4-aryl-4-(hydroxyimino)butyric acid esters.

Stereoselective reduction of α-alkoxycarbonylketene dithioacetals with the use of Me2Cu(CN)Li2

α-Alkoxycarbonylketene dithioacetals (1) were smoothly reduced by the higher order cyanocuprate Me2Cu(CN)Li2 at –20 °C to the corresponding vinyl sulphides (2) in high yields, with high stereoselectivity and generality.