The highly efficient and chemoselective α,α′-bis-substitution of alkanones is important in organic synthesis. Herein, a dimeric titanium cluster, Ti₂Cl₂(OPrⁱ)₆·2HOPrⁱ (Ti₂), is used in the Claisen–Schmidt condensation reaction, for the selectively activation of symmetrical ketones containing α,α′-methylene groups and production of α,α′-bis-substituted alkanones in high efficiency and chemoselectivity. The high efficiency and chemoselectivity can be extended to a variety of typical alkanones and aromatic aldehydes. Both of the oxo-bridged dimeric motif of Ti₂ and the ionic Ti–Cl bond are responsible for the high efficiency and chemoselectivity. 

Tetrahedron 

Available online 30 January 2016