The nadir (UK: /ËnÃ¦dÉªÉr/), (US: /ËneÉªdÉªÉr/) (from Arabic: ÙØ¸ÙØ±ââ / ALA-LC: naáºÄ«r, meaning counterpart) is the direction pointing directly below a particular location; that is, it is one of two vertical directions at a specified location, orthogonal to a horizontal flat surface there.
Asymmetric hydrogenation is a chemical reaction that adds two atoms of hydrogen preferentially to one of two faces of an unsaturated substrate molecule, such as an alkene or ketone.ne of these is in the asymmetric hydrogenation of N-unfunctionalized imines to give primary amines. Such species can be difficult to selectively reduce because they tend to exist in complex equilibria of imine and enamine tautomers, as well as (E) and (Z) isomers.
Hydrogenation Definition: Hydrogenation is a reduction reaction which results in an addition of hydrogen (usually as H2). If an organic compound is hydrogenated, it becomes more 'saturated'. Hydrogenation has many applications, but most people are familiar with the reaction as the one used to make liquid oils into semi-solid and solid fats.