Unprecedented reactivity of 1-alkynes with 2-chloroethanol promoted by cationic solvento(trifluoromethyl) platinum(II) complexes.: Synthesis of β-alkoxyalkenyl derivatives and X-ray structure of trans-[Pt{C(H)=C(Ph)OCH2CH2Cl}(CO)(PPh3)2][BF4]•Et2O

Reactions at ambient temperature of the solvento cationic trifluoromethyl complex trans[Pt(CF3)(PPh3)(2)(solv)] [BF4] with 1.5 equiv of 1-alkynes RC=CH (R = Ph, p-tolyl) and 2-chloroethanol afford in high yield the beta-alkoxyalkenyl complexes trans-[Pt(C(H)=C(R)-OCH2CH2Cl)(CO)(PPh3)(2)][BF4] (R = Ph(1), p-tolyl (2)). In these reactions the CF3 group is also converted to a CO ligand. Complexes 1 and 2 were characterized by spectroscopic techniques and 1 also by an X-ray diffraction analysis. Reaction of the alkynyl complex trans-[Pt(CF3)(C=C-p-tolyl)(PPh3)(2)] with 2-chloroethanol and 1 equiv of HBF4 gives the acetylide-carbonyl derivative trans-[Pt(C=C-p-tolyl)(CO)(PPh3)(2)][BF4] (3), which was also formed by reaction of trans-[Pt(CF3)(C=C-p-tolyl)(PPh3)(2)] with aqueous HBF4. Possible mechanisms of these reactions are discussed.