Kiitiro Utimoto

Stereoselective synthesis of 1,3-diol from β-hydroxyacylsilane via rearrangement of phenyl group from silicon to carbon

Abstract Treatment of β-hydroxyacyldimethylphenylsilanes with potassium fluoride in DMSO gave 1,3-diols stereoselectively via migration of phenyl group on silicon.

Preparation of 3-Methylenesilacyclobutane and its Use in Organic Synthesis

Abstract Treatment of 3-methylene-1,1-diphenylsilacyclobutane ( 1a ) with dihalo-melhyllithium provided ring expanded 2-halo-4-methylenesilacyclopentane. Heating a mixture of 1a and carbonyl compound such as PhCHO or PhCOMe at reflux in 1,2-dichloroethane afforded 5 methylene 1,1 diphenyl-2-oxa-1-silacyclohexane which was converted into 3-methylene-1,5-alkanediol monomethyl ether upon treatment with dimethyl acelal in the presence of Lewis acid catalyst. Treatment of ketoaldehyde (PhCOCH 2 CHO) with 1a under BF 3 · OEt 2 catalysis gave 3-methylene-1-phenyl-8 oxabicyclo[3.2.1]octane in one pot

Facile syntheses of α-bromo-α-silyl ketones and α-bromoacylsilanes from tert-butyldimethylsilyldibromomethane and carbonyl compounds

Abstract An addition of benzaldehyde to an ethereal solution of tert -butyldimethylsilyldibromo-methyllithium, derived from t -BuMe 2 SiCHBr 2 and lithium diisopropylamide, provided α-bromo-α-silyl ketone. The use of ketone instead of aldehyde afforded α-bromoacylsilane via a bromo silyl epoxide intermediate. Further treatment of the α-bromo-α-silyl ketone with butyllithium afforded lithium enolate which provided β-hydroxy-α-silyl ketone upon treatment with aldehyde in ether. The enolate gave α,β-unsaturated ketone or monosilyl ether of 2-acyl-1,3-diol in THF instead of ether. The use of isopropylmagnesium bromide in place of butyllithium also resulted in a formation of the corresponding magnesium enolate.