What is the Felkin ahn model?

Felkin-Ahn model: In Felkin-Ahn model, a nucleophile comes from the least hindered side. The best way to do Felkin-Ahn model is to draw a newmen projection. Then have the nucleophile attack from the smallest group. Here, the model shows that the nucleophile prefers to attack from the least hindered side.

What is Cram’s chelation model?

Chelation model According to Reetz, the Cram-chelate model for 1,2-inductions can be extended to predict the chelated complex of a β-alkoxy aldehyde and metal. The nucleophile is seen to attack from the less sterically hindered side and anti- to the substituent Rβ, leading to the anti-adduct as the major product.

What is Cram’s rule in chemistry?

Cram’s rule: As stated by Donald Cram of UCLA in 1952, “In certain non-catalytic reactions that diastereomer will predominate, which could be formed by the approach of the entering group from the least hindered side when the rotational conformation of the C-C bond is such that the double bond is flanked by the two …

Why is Burgi dunitz angle?

The Bürgi-Dunitz angle describes the angle of attack of a nucleophile at a carbonyl center. bond, and optimally so, too, would be the angle of nucleophilic attack, which would produce the most energetically optimal overlap between its HOMO and the LUMO of the carbonyl center.

What is cieplak model?

In organic chemistry, the Cieplak effect is a predictive model to rationalize why nucleophiles preferentially add to one face of a carbonyl over another. Proposed by Andrzej Stanislaw Cieplak in 1980, it predicts anomalous results that other models of the time, such as the Cram and Felkin–Anh models, cannot justify.

What is Saytzeff rule give suitable examples?

Answer: There are haloalkanes that can undergo elimination in two different ways resulting in two different products. Alkenes with less number of hydrogens on the double-bonded carbon atoms are the preferred product.

Are diastereomers mirror images?

Diastereomers are stereoisomers that are not related as object and mirror image and are not enantiomers. Unlike enatiomers which are mirror images of each other and non-sumperimposable, diastereomers are not mirror images of each other and non-superimposable.

What is donitz angle of trajectory?

The Bürgi–Dunitz angle (BD angle) is one of two angles that fully define the geometry of “attack” (approach via collision) of a nucleophile on a trigonal unsaturated center in a molecule, originally the carbonyl center in an organic ketone, but now extending to aldehyde, ester, and amide carbonyls, and to alkenes ( …

What is Burgi Dunitz’s trajectory?

The trajectory of this nucleophile is around 107-109° and this angle is called Bürgi-Dunitz angle; named after H. B. Bürgi and J. D. Dunitz who discovered the physical evidence that supports the this angle of attack (H. B. Bürgi, J. D. Dunitz, and E. Shefter, J.

What are axial and equatorial bonds?

The carbon bond to the non-ring atoms can be either axial or equatorial. Axial bonds are the bonds that form an 90∘ angle with the ring plane whereas equatorial bonds are the bonds that only make a small angle with the plane.