Preparation of pyranylidene complexes of ruthenium

Abstract

The reaction of the chloro-complex RuCl(η⁵-C₅H₅)(PPh₃)[P(OMe)₃] with alkylpropiolates HCCCOOR1 in alcohol R2OH affords pyranylidene derivatives [Ru(η⁵-C₅H₅){C(COOR1)C(H)C(H)C(OR1)O}(PPh₃){P(OMe)₃}]BPh₄ (1, 3) and alkoxycarbene complexes [Ru(η⁵-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 ¹H, ¹³C, ³¹P NMR) and by X-ray crystal structure determination of [Ru(η⁵-C₅H₅){C(COOMe)C(H)C(H)C(OMe)O}(PPh₃){P(OMe)₃}]BPh₄ (1).