Reaction of Ti(OiPr)4 or Zr(OPr)4 with 1 or 2 molar equiv of the 3-alkyl-substituted acetylacetone derivatives 3-acetyl-6-trimethoxysilylhexane-2-one or 3-acetylpentane-2-one not only gives the corresponding β-diketonate complexes but also results in about 15% hydrodeacylation of the β-diketone. With the stronger Lewis acid Al(OsBu)3 hydrodeacylation prevails. Hydrodeacylation is suppressed when a 1â¶5 ratio of metal alkoxide and β-diketone is reacted.