Synthesis and molecular structure of rac-methylenebis(4,5,6,7-tetrahydro-1-indenyl)titanium dichloride

The reaction of indenylpotassium with 0.5 equiv. of chloromethylpivalate yields bis(3-indenyl)methane (1). Double deprotonation of 1 with two equiv of BuLi, reaction with TiCl4 . 2THF and subsequent hydrogenation yields rac-methylenebis(4,5,6,7-tetrahydro-1-indenyl) titanium dichloride (3) in 16% overall yield. The molecular structure of (3) reveals a very small acute angle of 98.9(2)degrees at the methylene bridge carbon atom. (C) 1997 Elsevier Science S.A.