How many chiral centers?

[MedPR]

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Why isn't the nitrogen a chiral center?

 

[milski]

It's sp2 hybridized, it always has a plane of symmetry going through its three neighboring atoms.

 

[SaintJude]

Even though it does seem sterically hindered, I think the lone pair on the nitrogen may still allow for Nitrogen Inversion. Is this a case of sp2 or nitrogen inversion?

 

[MedPR]

I know it's not NH3 here, but isn't NH3 sp3 hybridized? 3 hydrogens and 1 electron pair = 4 electron domains = sp3..?

 

[milski]

I know it's not NH3 here, but isn't NH3 sp3 hybridized? 3 hydrogens and 1 electron pair = 4 electron domains = sp3..?

You might be right. All through my ochem course we used to draw the N as a flat three spoke structure and never discussed it as a chiral center. It seems that it is indeed sp3 and has a slightly pyramidal structure but quickly interchanges between its two possible states at room temperature. I guess the lack of a stable structure is the reason why it's not usually discussed as a chiral center.

 

[Temperature101]

I thought it was 4 chiral center...What happen to the carbon that is connected to the first oxygen?

 

[milski]

I thought it was 4 chiral center...What happen to the carbon that is connected to the first oxygen?

Two of its substituents are exactly the same.

 

[Temperature101]

two of its substituents are exactly the same.

OK ...I see it now