Masatoshi Mihara

Convenient N-formylation of secondary amines: KF-Al2O3-Promoted synthesis of formamide derivatives via dichlorocarbene generated from chloroform

The treatment of secondary amines with chloroform in the presence of KF-Al 2 O 3 in acetonitrile brought about highly facile and efficient N-formylation to give the corresponding formamides in good to excellent yields. TheN-formylation reaction not only involves mild conditions, simple operations and high yields but high chemoselectivity as well.

Metal zinc-promoted gem-bisallylation of acid chlorides with allyl chlorides in the presence of chlorotrimethylsilane

Treatment of acid chlorides (2) with allyl chlorides (1) in the presence of zinc dust and a catalytic amount of chlorotrimethylsilane (TMSCl) in THF brought about highly facile and effective coupling to give the corresponding gem-bisallylation products, 4-hydroxy-penta-1,6-dienes (3), in good to excellent yields. These reactions are assumed to proceed through allylzinc intermediates generated in situ.

Transition-Metal-Free and Oxidant-Free Cross-Coupling of Arylhydrazines with Disulfides: Base-Promoted Synthesis of Unsymmetrical Aryl Sulfides

A novel synthesis of unsymmetrical aryl sulfides, which requires no transition metal catalyst and no oxidant, was developed. This base-promoted cross-coupling reaction proceeded using arylhydrazines and 1 equiv amount of disulfides under inert gas conditions to afford the unsymmetrical aryl sulfides in good yields.

A New Simple Method for the Synthesis of Thiophene Derivatives — Generation of Thiocarbonyl Ylides form S-a-(Dimethylphenylsilyl)benzyl Acylates and Their Cycloaddition with Acetylenic Dipolarophiles —

The cycloaddition of S-α-(dimethylphenylsilyl)benzyl acylates (1) with acetylenic dipolarophiles via 1,4-silatropy proceeded readily to afford thiophene derivatives. The reaction of thioesters (1) with 1-diethylamino-1-propyne (A), an electron-rich acetylenic dipolarophile, gave 5-aryl-3-diethylamino-4-methyl-2-phenylthiophenes (3) and 4-aryl-2-diethylamino-3-methyl-5-phenylthiophenes (4). When dimethyl acetylenedicarboxylate (DMAD), an electron-deficient alkyne, was used, the reaction of thioesters (1) afforded thiophene derivatives (4) exclusively.