Shin-ichiro Matsunaga

A Novel Class of Herbicides (Specific Inhibitors of Imidazoleglycerol Phosphate Dehydratase)

A new mode of herbicidal action was established by finding specific inhibitors of imidazoleglycerol phosphate dehydratase, an enzyme of histidine (His) biosynthesis. Three triazole phosphonates inhibited the reaction of the enzyme with Ki values of 40 [plus or minus] 6.5, 10 [plus or minus] 1.6, and 8.5 [plus or minus] 1.4 nM, respectively, and were highly cytotoxic to cultured plant cells. This effect was completely reversed by the addition of His, proving that the cytotoxicity was primarily caused by the inhibition of His biosynthesis. These inhibitors showed wide-spectrum, postemergent herbicidal activity at application rates ranging from 0.05 to 2 kg/ha.

New one carbon homologation reagents utilizing electrochemical oxidation of organosilicon compounds

Abstract Phenylthio(trimethylsilyl)methane, phenylthiobis(trimethylsilyl)methane, methoxy(trimethylsilyl)methane, and methoxybis(trimethylsilyl)methane are deprotonated and the resulting anions are alkylated with electrophiles such as organic halides. The alkylation products are readily converted into the corresponding dimethyl acetals or methyl esters by electrochemical oxidation in methanol.

Methoxy(trimethylsilyl)methane and methoxybis(trimethylsilyl)methane as new reagents for homologation

Abstract New synthons of formyl anion (methoxy(trimethylsilyl)methane ( 1 )) and alkoxylcarbonyl anion (methoxybis(trimethylsilyl)methane ( 2 )) have been developed using oxidative cleavage of the carbon-silicon bond by anodic oxidation.

Electrochemical oxidation of acylsilanes

Abstract Oxidation potentials of acylsilanes were found to be much less than those of the corresponding ketones and aldehydes. Electrochemical oxidation of acylsilanes resulted in facile cleavage of the carbon-silicon bond and introduction of oxygen and nitrogen nucleophiles at the carbonyl carbon. Therefore acylsilanes serve as a synthetic equivalent of acyl cations.

Trimethylsilyl triflate promoted 1,4-addition of silyl phosphites to cyclic enones

Abstract A catalytic amount of trimethylsilyl triflate (TMSOTf) remarkably facilitates the selective conjugate addition of a variety of silyl phosphites, prepared in situ from dialkyl phosphites and N , O -bis(trimethylsilyl)acetamide, to cyclic enones giving 1,4-adducts in high yields.