IIT JEE , AIEEE Forum - Chemistry , Organic Chemistry

its_my_life_001

why does Walden Inversion takes place in SN2 reactions???

taruntanuj007

See the inversion occurs because of the baxk side attack since carbocation is unstable so t attack is very fast and its like an umbrella changing its orientation!!!

madhusudan.chavan

10239

Waldon inversion occurs at a tetrahedral carbon atom during an S_N² reaction when the entry of the reagent and the departure of the leaving group are synchronous. The result is an inversion of configuration at the center of attack.

Refer to mechanism of S_N² reaction, backside attack by nucleophile, transition state in which attacking group-the carbon atom attacked ?and the leaving group are in a line.

amangem

see.... first of all , sn2 machanism doesnt involve carbocation.

then as far as inversion is concerned.....
see when the nucleophile aproaches the molecule , due to the leaving groups repulsion it has to approach from the backside ..... so in the transition state , umbrella turn up takes place ... that is inversion of configuration. it basically can be visualised as the process of retaining the tetrahedral structure by the compound .
refer to the diagramatic explaination to make thing clearer

robinphilip1989

all above explainations ar correct plz note that a pentavalent carbon transition state is formed.

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