INSERTION OF ISOCYANIDES INTO RE-C BONDS

Isocyanide-substituted Re alkyl complexes cis-p-XC(6)H(4)CH(2)Re(CO)(4 )(CN-p-tolyl) (X = Cl, OMe) were prepared from the PdO-catalyzed react ion of p-XC(6)H(4)CH(2)Re(CO)(5) (X = Cl, OMe) with p-tolyl isocyanide . On heating in toluene these complexes undergo isocyanide insertion i nto the Re-C bond to afford iminoacyl complexes which further react to orthometallate the p-tolyl ring. An X-ray crystal structure determina tion on (CO)(4)Re(C6H3(CH3))N(H)=CCH(2)C(6)H(4)p-Cl (3a) revealed that C19H13ClO4NRe crystallizes in the monoclinic space group P2(1)/c with 4 formulas per unit cell. Unit cell parameters are a = 9.799(1), b = 15.252(2), c = 13.569(2) Angstrom and beta = 110.788(8)degrees. The st ructure shows Re-C bond distances indicative of substantial carbenoid character.