Chemistry Letters, Vol.39, No.7, 723-725, 2010
[2+2+1] Cycloaddition between Alkynes, Acrylates, and Titanocene(II): Regioselective Formation of 5-Alkoxycarbonyltitanacyclopent-2-enes and Their Addition to Carbonyls
5-Alkoxycarbonyltitanacyclopent-2-enes were produced regioselectively by the [2 + 2 + 1] cycloaddition between alkynes, acrylates, and titanocene(II) reagent Cp2Ti[P(OEt)(3)](2). Although the titanacycles were inactive toward carbonyl compounds, their addition proceeded in the presence of titanocene(II).