SYNTHESIS OF DISUBSTITUTED AND MONOSUBSTITUTED ALLENYLIDENE-RUTHENIUM [(PH(2)PCH(2)PPH(2))(2)CLRU=C=C=C(Y)R]PF6 AND ACETYLIDE COMPLEXES BY ACTIVATION OF PROP-2-YN-1-OLS

The reaction of cis-RuCl2(dppm)(2), 1 (dppm = Ph(2)PCH(2)PPh(2)), with HC=C-C(OH)R(2) and NaPF6 affords stable 3,3-disubstituted allenylidenes [(dppm)(2)ClRu=C=C=CR(2)]PF6, 3a-e. The activation of monosubstituted propargyl alcohols with 1 and NaPF6 allows the general access to stable secondary allenylidenes [(dppm)(2)ClRu=C=C=C(H)R]PF6 4f-i (R = Ar), 5 (R = (E)-CH=CHPh) or that to (dppm)(2)ClRu=C=CH-CH=CH2]PF6 6. Complex 1 reacts with HC=C-C(=CH2)CH3, promotes the 1,4 migration of the (HC=C) proton, and gives [(dppm)(2)ClRu=C=C=CMe(2)]PF6, 3e, which can be deprotonated at the C(4) carbon. Allenylidene 3a (R = Ph) easily adds nucleophile at the C(3) carbon to give the acetylide (dppm)(2)ClRu-C=C-CPh(2)(OMe), 9a, with MeONa, and (dppm)(2)ClRu-C=C-CPh(2)H, 12a, with NaBH4. By contrast, secondary allenylidenes 4f,g,i with MeONa give mixed hydride acetylide complexes trans-(dppm)(2)(H)Ru-C=C-CH(OMe)R, 10, and with NaBH4 (dppm)(2)-(Cl)Ru-C=C-CH(2)R.