Yoshiyuki Onishi

Indium trichloride catalyzed reductive Friedel-Crafts alkylation of aromatics using carbonyl compounds

Abstract Reductive Friedel-Crafts alkylation of aromatics with aldehydes or ketones using chlorodimethylsilane as a hydride source was effectively promoted by a catalytic amount of indium trichloride, whereas a popular type of Friedel-Crafts catalysts showed less effect.

Novel reductive Friedel-Crafts alkylation of aromatics catalyzed by indium compounds: Chemoselective utilization of carbonyl moieties as alkylating reagents

Abstract Reductive Friedel-Crafts alkylation of aromatics with ketones or aldehydes was characteristically catalyzed by indium compounds in preference to general catalysts like AlCl3 and BF3, where hydrosilanes would play an important role both as a hydride donor and as a co-catalyst. Chemoselective utilization of ketone moieties as alkylating reagents took place even in the presence of halogen, ester or ether moieties which are very susceptible under traditional Friedel-Crafts conditions. Discussion on a plausible intermediate was carried out by some controlled experiments.

Remarkable enhancement of lewis acidity of chlorosilane by the combined use of indium(III) chloride

Abstract A combination of InCl3 and R3SiCl provided a strong Lewis acid catalyst for such reactions as allylation, hydrosilation and Friedel–Crafts alkylation. Especially, catalytic Sakurai–Hosomi-type allylation was accomplished with high yield and selectivity. The silicon atom is assumed to be the acidic center of the combined system, and the catalytic activity largely depends on the substituents on the silicon center.

Reaction of alcohols and silyl ethers in the presence of an indium/silicon-based catalyst system: Deoxygenation and allyl substitution

An In(III)/Si catalyst system effects the direct allyl substitution of alcohols and silyl ethers under mild conditions. A deoxygenation of alcohols is also promoted by InCl3 catalyst. This method requires no pretreatment or protection of hydroxy groups or deprotection of siloxy groups. The completion of the catalytic allylation depends on the low oxophilicity and high halophilicity of In(III) halide species, and other representative Lewis acids such as AlCl3 and BF3 have no catalytic activity for the allylations. The oxophilicity and halophilicity are also demonstrated by NMR studies.

Indium compound-catalyzed deoxygenative allylation of aromatic ketones by a hydrosilane–allylsilane system

Abstract A combination of chlorodimethylsilane and allyltrimethylsilane effectively promoted the deoxygenative allylation of aromatic ketones in the presence of a catalytic amount of an indium compound to give the terminal alkenes. Indium trihalide or metallic indium showed high catalytic activity.