Enediolato complexes

Enediolato complexes have been prepared by deprotonation of a-diketones (Section II.A.2.a) or by using CO or carbonyl complexes (Section IV.B). 

The reactivity of the dialkyl complexes TiR2(LL)2 (LL = N,N -dimethylaminotroponiminato) has been widely studied. Reactions with CO and aldehydes or ketones afford unsymmetrical diolato complexes that convert to the corresponding vicinal diols after hydrolysis. CO and acetylene react to form the oxametallacyclopentene complex. Treatment with RNC yields the free imine and low-valent titanium species (Scheme 131). In the reaction with BucNC, free ButN=CMe2 is formed and the addition of benzaldehyde or benzyl reagents affords titanium diolato or enediolato complexes. Thiolato-alkoxo or amido-alkoxo titanium complexes can also be similarly prepared (Scheme 132).123-125... 

Compound 95 has been shown to be a useful precursor for the synthesis of a range of open and closed dienyl complexes, in particular, the preparation of open and closed ruthenocene. A series of 1,5-, 2,4- and 3-substituted pentadienyl complexes of ruthenium have been prepared and characterised. A series of heteroatom-containing diene complexes of type 96 have been synthesised. 1,2-Diketones were shown, however, not to coordinate in this fashion, rather to undergo a one-electron transfer reaction giving enediolato-containing complexes. Complexes of type 97 have been synthesised on treatment of the triple decker complex [ (CpR)Co 2(p-r r -C6F[5Me)] with acetone, cyclohexanone, and acetophenone. The mechanism of formation was said to proceed through a... 

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