Preparation of Pyranylidene Complexes of Ruthenium

The reaction of the chloro-complex RuCl(η(5)-C5H5)(PPh3)[P(OMe)3] with alkylpropiolates HC≡CCOOR1 in alcohol R2OH affords pyranylidene derivatives [Ru(η(5)-C5H5){=C(COOR1)C(H)C(H)C(OR1)O}(PPh3){P(OMe)3}]BPh4 (1, 3) and alkoxycarbene complexes [Ru(η(5)-C5H5){=C(OR2)(CH2COOR1)}(PPh3){P(OMe)3}]BPh4 (2, 4). A reaction path for the formation of compounds 1-4, involving reactions on a vinylidene intermediate complex, is also discussed. The complexes were characterized spectroscopically (IR and (1)H, (13)C, (31)P NMR) and by X-ray crystal structure determination of [Ru(η(5)-C5H5){=C(COOMe)C(H)C(H)C(OMe)O}(PPh3){P(OMe)3}]BPh4 (1).