Conversion of η2-phosphinocarbene complexes into tungstaphosphabicyclo[1.1.0]butanone units

Cationic eta(2)-phosphinocarbene complexes [eta(2)-C5H5(CO)(PMe3)<(W = C(R)-P)over bar>Ph-2][PF6] (R = Me, Ph, Tol) react at -78 degrees C with alkyl isonitriles R'NC (R' = Me, Bu-t) to provide tungstaphosphabicyclo[1.1.0]butanone complexes [eta(5)- C5H5(R'NC)(PMe3)<(W-C(O)-C)over bar>(R)-PPh2][PF6] in high yields. The constitution of the yellow bicyclic compounds was determined by spectroscopic investigations and, in the case of the 4-methylphenyl substituted compound 2c, additionally by X-ray single crystal structure analysis. Crystal data for 2c are as follows: space group P2(1)/n (No. 14), a = 907.80(10), b = 3658.1(6), c = 1085.2(2) pm, alpha = 90 degrees, beta = 106.27(1)degrees, gamma = 90 degrees, Z = 4. (C) 1998 Elsevier Science S.A.