Reactions of [(PPh3)2Pt(η3-CH2CCPh)]+ with oxygen nucleophiles and chemistry of resultant [(PPh3)2Pt(η3-CH2C(OR)CHPh)]+ complexes

The η3-allenyl/propargyl complex [(PPh3)2Pt(η3-CH2CCPh)]OTf (1OTf) undergoes addition reactions with a number of oxygen nucleophiles in CH2Cl2 solution at ambient temperature. With H2O, it yields the binuclear oxygen-bridged η3-allyl [{(PPh3)2Pt(η3-CH2CCHPh)}2O](OTf)2 (2(OTf)2). With primary and secondary alcohols, it rapidly affords the η3-(2-alkoxyallyl) complexes [(PPh3)2Pt(η3-CH2C(OR)CHPh)]OTf (R=Et (3OTf), i-Pr (4OTf), CH2CMe3 (5OTf), CH2CHCH2 (7OTf)), whereas with tertiary alcohols, in slower reactions, it gives both 2(OTf)2 and [(PPh3)2Pt(η3-CH2C(OR)CHPh)]OTf (R=CMe3, C(Me)2Et (6OTf)). There is no reaction at ambient temperature between 1OTf and phenols; however, 1OTf and PhOH afford [(PPh3)2Pt(η3-CH2C(OPh)CHPh)]OTf (8OTf) in the presence of NEt3. Competition studies reveal the following reactivity order, attributed to steric effects: Me3CCH2OH(1.0)