Allenylation of Functionalized Carbonylic Compounds

When valuable alkenyl groups are used, the use of alkyl alkenyl titanocene prepared from the monochlorotitanocene also leads to the unstable titanocene alkenylidene intermediate that is similarly trapped in situ by the carbonyl compound [66]. 

Preparation of Functionalized Substrates via Titanium (ii) Alkoxide Derivatives 

1 Generation of 2-Alkene, rj2-k V.yne Complexes and their Utilization as Vicinal Dianionic Species 

Obviously, as carbonyl derivatives react with titanium derivatives the presence of functional groups is therefore limited. 

However, a very useful adaptation of the original protocol for the conversion of esters to cyclopropanols with titanacydopropane towards a highly versatile preparation of cydopropylamines has been developed [68], N,N-dialkylaminocyclopro-panes with up to three additional substituents are readily obtained from carboxylic acid N,N-dialkylamides and ethyl- as well as substituted ethylmagnesium bromide in the presence of titanium tetraisopropoxide. These transformations were also possible with substoidiiometric amounts of Ti(OPr-i)4, but the yields were significantly better with stoichiometric amounts. 

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