text: The Tebbe reagent is synthesized from titanocene dichloride and trimethylaluminium in toluene solution.
  ::CpTiCl + 2 Al(CH) → CH + CpTiCHAlCl(CH) + Al(CH)Cl
  After about 3 days, the product is obtained after recrystallization to remove Al(CH)Cl.  Although syntheses using the isolated Tebbe reagent give a cleaner product, successful procedures using the reagent "in situ" have been reported. Instead of isolating the Tebbe reagent, the solution is merely cooled in an ice bath or dry ice bath before adding the starting material.
  An alternative but less convenient synthesis entails the use of dimethyltitanocene (Petasis reagent):
  ::CpTi(CH) + Al(CH)Cl → CpTiCHAlCl(CH) + CH
  One drawback to this method, aside from requiring CpTi(CH), is the difficulty of separating product from unreacted starting reagent.