Toshio Kakui

Oxidative cleavage of silicon-carbon bonds in organosilicon fluorides to alcohols

Abstract Certain functional silyi groups have been shown to be synthetically equivalent to the OH group. All of the C-Si bonds in organosilicon fluorides, K 2 (RSiF 5 ] and R n SiF 4-n , (n = 1,2,3) are cleaved by m-chloroperbenzoic acid (MCPBA) in DMF to give the corresponding alcohols in high yields. Although the reaction with RSiF 5 2- and RSiF 3 proceeds without any additive, cleavage of R 2 SiF 2 and R 3 SiF requires, respectively, a catalytic or excess amount of KF. A triorganoethoxysilane also undergoes similar oxidative cleavage reactions in the presence of an excess amount of KF. The MCPBA-oxidation of exo - and endo -2-norbornyl-silicate and -trifluorosilane proceeds stereospecifically with retention of configuration at carbon. A remarkable solvent effect has been observed in the oxidative cleavage of RSiF 3 . A plausable mechanism involves a hexacoordinate silicon species in which the organic group intramolecularly migrates from Si to O of the coordinated MCPBA.

Solid state reactions of organopentafluorosilicates with copper(I) and copper(II) salts

Abstract Two types of solid state reaction of K 2 [RSiF 5 ] have been developed: (1) CuCl promoted homo coupling of alkenyl- and phenyl-silicates, and (2) formation of RH fraom alkyl- and alkenyl-silicates by heating with CuF 2 ·2H 2 O.

A stereoselective synthesis of symmetrical (E,E)-1,3-dienes by silver(I) promoted homo coupling of (E)-alkenylpentafluorosilicates☆

Abstract symmetrical ( E,E )-1,3-dienes can be prepared by high yields from ( E )-alkenylpentafluorosilicates either by treating with silver fluoride in acetonitrile or by stirring with silver nitrate in water/ether.

Solvolytic cleavage of alkenylpentafluorosilicates catalyzed by copper(II) acetate. A stereoselective synthesis of (E)-alkenyl ethers from alkynes

Abstract ( E )-Alkenylpentafluorosilicates, obtainable from acetylenes via hydrosilylation-silicate formation, react with alcohols in the presence of a catalytic amount of copper(II) acetate under an atmosphere of air (oxygen) at room temperature to form ( E )-alkenyl ethers stereoselectively in satisfactory yields. Similar reaction with water gives aldehydes.

(E)-alkenyl thiocyanates from (E)-alkenylpentafluorosilicates by the oxidative cleavage with copper(II) thiocyanate

Abstract ( E )-Alkenylpentafluorosilicates react with copper(II) thiocyanate in DMF at ambient temperature to give ( E )-alkenyl thiocyanates stereoselectively in high yields.