EXTENSION OF THE BENKESER REACTION TO THE REDUCTIVE TRICHLOROSILYLATION OF MAIN-GROUP ELEMENT CHLORIDES

Chlorophosphanes RR'PX 1 (1a: R, R'=i-propyl; 1b: R=t-butyl, R'= i-pro pyl; 1c: RR'=3-methylphosphol-2-enyl) react with trichlorosilane and t riethylamine to provide trichlorosilylphosphanes RR'PSiCl3 2a-c and tr iethylammonium chloride in high yield. In the case of the reaction of dichlorophosphanes RPCl(2) 3 with trichlorosilane and triethylamine, d ouble trichlorosilylation provides bis(trichlorosilyl)phosphanes RP(Si Cl3)(2) 4a-f (a: R=Pr-i, b: R=(t)Bu, c: R=1-adamantyl, d: R=(Me(3)Si)( 2)CH, e: R=NEt(2), f: R=N(Pr-i)(2)). However, depending on the nature of R, reactions may also lead to cyclophosphanes (RP)(n) 5 (thus 4a an d 4e could not be isolated in a pure state) or to trichlorosilylphosph anes RP(H)SiCl3 6. With 3g (R=2,4,6-(t)Bu(3)C(6)H(2)), mixtures of 6g and 2,4,6-(t)Bu(3)C(6)H(2)PH(2) are formed. Chlorotrimethylstannane 7 reacts with trichlorosilane and triethylamine providing the trichloros ilylstannane R(3)SnSiCl(3) (R=CH3) 8.