REACTIONS OF [RUCL(PME3)2(CP)] WITH ALIPHATIC ALKYNOLS LEADING TO CATIONIC VINYLVINYLIDENE AND NEUTRAL ENYNYL COMPLEXES AND REACTIONS OF THE ENYNYLS WITH HETEROALLENES

Reactions of [RuCl(PMe3)2(Cp)] with 1-ethynylcyclohexanol or 1-ethynylcyclopentanol and NH4PF6 lead to cationic cycloalkenyl vinylidene complexes [Ru(C = CHR)(PMe3)2(Cp)][PF6] (1, R = cyclohexenyl, and 2, R = cyclopentenyl) in ca. 80 % yield. Similarly, 3-isopropyl-4-methyl-1-pentyn-3-ol (HC = CC(OH)(CHMe2)2) produces [Ru[C = CHC(CHMe2)(= CMe2)](PMe3)2(Cp)][PF6] (3) in 77 % yield. The structure of the 1-ethynylcyclohexanol product 1 was determined by X-ray diffraction (R = 6.3 %, R(w) = 9.3 %). The molecule contains a cyclohexenylvinylidene ligand bonded to the ruthenium atom by a short Ru-C bond (1.843 (7) angstrom). Complexes 1-3 are reversibly deprotonated by sodium methoxide to yield the corresponding enynyl complexes [Ru(C = CR)(PMe3)2(Cp)] (4, R = cyclohexenyl, and 5, R = cyclopentenyl) and [Ru[C = CC(CHMe2)(= CMe2)](PMe3)2(Cp)] (6). The reaction of enynyl 4 with carbon disulfide gave a [2 + 2] cycloadduct via nucleophilic attack of the enynyl beta-carbon on CS2. The reaction of 4 with methyl isocyanate gave only isocyanate polymers. Attempted reactions with other heteroallenes were not successful.