Pentafulvene-derived η3-allyltitanocenes as intermediates for the stereoselective functionalization of 5-membered carbocycles

Allyltitanocene complexes can be generated by reacting pentafulvenes with DIBAL-H and Cp2TiCl2. Their coupling with aldehydes affords homoallylic alcohols in a highly regio- and stereoselective manner. The potential of this method for the stereoselective synthesis of cyclopentane derivatives is illustrated.