ATTEMPTED GENERATION OF CP(CO)2RE(MU-H)PT(PPH3)2[C(CH3)=CHCH3] FROM REACTION OF CP(CO)2REH- WITH (PPH3)3PT[(E)-C(CH3)=CHCH3]+ PRODUCES CP(CO)2RE(CIS-CH3CH=CHCH3)

Previously we proposed Cp(CO)2Re(mu-H)Pt-(PPh3)2[C(CH3) = CHCH3] (II) as a possible intermediate in the reaction of 2-butyne with Cp(CO)2Re(mu-H)Pt(H)-PPh3)2 (1) to give Cp(CO)2Re(cis-CH3CH = CHCH3) (cis-2). In an attempt to independently synthesize II, the reaction of K+Cp(CO)2ReH- (3) with (PPh3)3Pt[(E)-C(CH3) = CHCH3]+CF3SO3- (cis-4) was studied and conversion to cis-2 was observed, but intermediate II was not detected. The reaction is stereospecific: trans-4 reacted with 3 to produce trans-2. K+Cp(CO)2ReD- (3-d) reacted with trans-Pt[C(CH3) = CH2](CF3SO3)(PPh3)2 (5) to give Cp(CO)2Re(CH2 = CDCH3) (6-d), which demonstrated that 3 is the hydride source in these reactions.