Synthesis and properties of novel dialkylaminocarbenium salts

Novel dialkylaminocarbenium salts with metallocomplex counter ions were prepared by the reaction of phosgene with either DMF or tetramethylurea in the presence of metal chlorides. Reactions of organosilicon amides with phosgene gave corresponding carbenium salts, while organosilicon ureas yielded aminoiminocarbenium salts. Dialkylaminochlorocarbenium salts were reduced with hydrosilanes to give dialkylaminocarbenium, salts and can be easily hydrolyzed to afford either amides or ureas. Pathways of the reaction with water and alcohols depend on the nature of reagent and the reaction conditions. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1035–1040, May 1997.     

1,2 → 1,1-Migration of Silyl Group. Formation of 1,1-Bis(dichloromethylsilyl)-2-chloroethane in Catalytic Hydrochlorination of 1,2-Bis(dichloromethylsilyl)ethylene

Hydrochlorination of 1,2-bis(silyl)ethylenes of the general formula Me_nCl_3-n SiCH = CHSiMe_n· Cl_3-n , where n = 0-3, in the presence of FeCl₃ was carried out. By NMR spectroscopy it was shown that in the case of the MeCl₂Si derivative the major product is 1,1-bis(silyl)chloroethane and the minor product is its isomeric 1,2-bis(silyl)chloroethane (4:1). A reaction scheme is proposed, that includes isomerization of the intermediate bis(silyl)ethyl cation.     

Organosilicon synthesis of isocyanates: I. Synthesis of isocyanates of the furan, thiophene, and mono-and polyfluorophenyl series

A convenient synthesis of known and unknown isocyanates of the furan, thiophene, and mono-and polyfluorophenyl series, involving silylation of starting amines with hexamethyldisilazane or chlorotrimethylsilane, followed by phosgenation of the resulting N-silyl-substituted amines. An unusual high-temperature rearrangement of 3-(methoxycarbonyl)-4,5-dimethylthiophene-2-yl isocyanate into its 5-ethyl isomer. ortho-Fluorine substituent in anilines decreases the yield of isocyanates, whereas 2,3,5,6-tetrafluorophenyl isocyanate exists for only a short time as a 5% toluene solution.