Imines and ketones

As such, a more thorough description of the energetics of nitroso compounds may well logically appear in a future Patai volume on functional groups devoted to carbon-containing double bonds such as monoalkenes, imines and ketones and aldehydes, since oximes would seem to belong with these functionalities. 

Prochirality Planar molecules possessing a double bond such as alkenes, imines, and ketones, which do not contain a chiral carbon in one of the side chains, are not chiral. When these molecules coordinate to a metal a chiral complex is formed, unless the alkene etc. has C2V symmetry. In other words, even a simple alkene such as propene will form a chiral complex with a transition metal. So will trans-2-butene, but cis-2-butene won t. If a bare metal atom coordinates to cis-2-butene the complex has a mirror plane, and hence the complex is not chiral. It is useful to give some thought to this and find out whether or not alkenes and hetero-alkenes form chiral complexes. One can also formulate it as follows complexation of a metal to the one face of the alkene gives rise to a certain enantiomer, and complexation to the other face gives rise to the other enantiomer. 

Several of the reactions described in Section 6.16.2.4.6.1 are two-step reactions. After the initial [2+1] addition of the silylene to the multiple bond, a second insertion reaction of a silylene into a reactive Si-X bond of the cyclopropane derivative takes place yielding four-membered ring compounds. Examples are the reactions with alkynes, nitriles, imines, and ketones. 

Thus, the selectivities, deactivation mechanisms, and potential transformations of alkoxo and amido intermediates in such reactions are not well understood. It is even rare for transition metal amido and alkoxo complexes to be clearly identified as intermediates in catalytic chemistry. The hydrogenation of imines and ketones presumably involves such intermediates [68], but they have not been clearly detected in these reactions [69]. The catalytic reduction of CO on surfaces may involve alkox-ides, but well-characterized homogeneous analogs are unusual [58]. 

The less important double bonds to nitrogen (imines) are very similar but now there is only one lone pair on nitrogen and a second G bond to whatever substituent is on the nitrogen atom. Looking down on the planar structures of alkenes, imines, and ketones we see only the ends of the p orbitals but the rest of the structures are clearly related. 

There are several other chemicals, which induce pel-liculization of gelatin. These are saccharides, e.g., glucose and aldose sugars imines and ketones dyes like FD C red No. 3 and hydrogen peroxide,... 

New synthesis of pyridones using conjugate addition reactions of active methine compounds to alkynyl imines and ketones 06Y251. 

A reaction of mechanistic, if not preparative, interest is the addition of diazomethane to the ketenimine (320), from which 3,3-dimethylcyclobutanone is obtained in 5% yield after hydrolysis. A stepwise addition of CH2 units, via a cyclopropanone imine, is evidently involved, emphasizing the resemblance of the imine and ketone function in these compounds. 

Vdclavik, J. L Kuzma, M. Pfech, J. Kader, P. Asymmetric transfer hydrogenation of imines and ketones using chiral RuIICl(T 6-p-cymene)[(S, S)-N-TsDPEN] as a catalyst A computational study. Organometallics 2011, 30, 4822-4829. 

Sugasawa has explored the use of vinylaminodichloro- and vinyloxyamino-chloro-boranes, generated from imines and ketones respectively, in the aldol reaction. The yields in the reactions were moderate to high (Scheme 75). In an... 

Chirik and co-workers described the electron-rich Fe-CNC dinitrogen pincer complexes 41 which were effective for the catalytic hydrogenation of unfunctionalized alkenes (Figure 13.3). ° Furthermore, the first example of zincocene-NHC adducts 42 was evaluated in the catalytic hydrogenation of imines and ketones (Figure 13.3). ... 

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