Okay, and now we have the third task.

It was to give an example of an anti-selective oxidation and an anti-selective reduction.

And how is the anti-selectivity influenced?

Okay, as an example of an anti-selective reaction we have the well-known Scherplet Epoxy reaction.

As a substrate for this reaction we have a primary or secondary alkyl alcohol.

The target product is epoxy alcohol, where these preserved epoxides can be converted into alcohol, diol, ether and other compounds.

That is why this Scherplet Epoxy reaction is very important in the chemistry industry.

Because it is an epoxidation we need an oxidizing agent, which is a hydroperoxide compound.

Most of the time it is the butyl hydroperoxide.

This anti-selective oxidation is produced by a sterile catalyst.

This is a cat complex, where the precursors for this complex are tetraesophobin, titanate, and ethyl tartrate, or DET.

For this DET connection there are two different esterisomers or enantiomers that can be used.

There is this R-R configuration and also a R-S configuration.

The only difference is the spatial arrangement of the hydroxide and hydrogen ligands.

This enantioselectivity of the reaction leads to the formation of a specific enantiomer, the epoxy alcohol, as we can see here.

This selectivity is actually very dependent on the composition and the outcome of the complex.

This means that a specific product is preferred depending on which DET is used.

This means that the selectivity or enantioselectivity is achieved by the addition of DET.

The spatial configuration of DET determines the contact site of the epoxy.

As we can see here, this contact point can be either below or above the planar reduct.

And then a specific product will be created.

As an example for an enantioselectivity reduction, there is also the well-known asymmetric Na-Yori-hydration.

This is a process for the enantioselectivity reduction of ketones.

It was discovered by Ryoji Nyori, that's why it's called that.

It is actually very useful nowadays, for example when producing drugs.

And here we have only an example of a possible reaction, where we have the same ethyl, so the same ketone,

and two different reducted enantiomers can be created.

And how does this happen? Or how can this be influenced so that one of the two reactions is benefited?

It is completely dependent on the used catalyst.

And actually the elfo of this process is at the catalyst.

This is a cryalircat, specifically a rutenium metal complex,

where these phosphine bonds are used as ligands, the so-called bind-up ligands.

And here there is a very simplified example of a catalytic reaction for an asymmetric reaction.

We first have our cat precursor, then the cat is activated.

The first step is the ketone coordination.

And at this very moment the selectivity is determined.

Depending on how the ketone bond coordinates, i.e. coordinates at the metal center,

a certain enantiomer product will be created.

And how can this coordination of the reduct be influenced and the selectivity adjusted?

The ligands play a very important role.

They direct the coordination of substrate at metal to the hysterical background.

This is, this arrangement of the ligands can benefit a certain overcurrent state.

And that means that after the choice of the chiral phosphine ligands or the catalyzer enantiomer,

the selectivity can be adjusted.