Aza-[2,3]-Wittig Rearrangement: Mechanism | Examples

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The rearrangements reactions are important Name reaction in organic chemistry. Wittig rearrangement, first reported by G. Wittig and L. Löhmann in 1942, The Wittig rearrangement converts α-metalated ethers to metal alkoxides, yielding secondary or tertiary alcohols. Its nitrogen analog, the aza-Wittig rearrangement, transforms α-metalated tertiary amines into rearranged metal amides, producing homoallylic secondary amines. This rearrangement features inversion of configuration and is slower and less selective than its ether counterpart. Unlike the Stevens and Sommelet-Hauser rearrangements, which involve quaternary ammonium salts, the aza-[2,3]-Wittig rearrangement is typically hindered unless ring strain is relieved.

Aza-[2,3]-Wittig Rearrangement

Aza-[2,3]-Wittig rearrangement Mechanism

The aza-[2,3]-Wittig rearrangement occurs via a concerted mechanism involving a six-electron, five-membered cyclic transition state. According to Woodward-Hoffmann rules, this thermally allowed rearrangement proceeds suprafacially, resulting in a one-step SNi reaction that forms carbon-carbon bonds through allyl inversion. The process transposes the heteroatom from an allylic to a homoallylic position, driven by the transfer of a formal negative charge from the less electronegative α-carbon to the more electronegative heteroatom. 2 3-wittig rearrangement mechanism.

Aza-[2,3]-Wittig rearrangement Mechanism | 2 3-wittig rearrangement mechanism

Aza -[ 2 3 ]-Wittig rearrangement examples

these are the following examples of Aza -[ 2 3 ]-Wittig rearrangement 

Aza -[ 2 3 ]- wittig rearrangement example

Related Reactions:

  1. Aza-Claisen Rearrangement
  2. Aza-Cope Rearrangement
  3. Aza-Wittig Reaction :Mechanism | Examples
  4. Sommelet-Hauser rearrangements

References:

  1. https://www.sciencedirect.com/
  2. Organic Chemistry Portal “
  3. https://pubs.rsc.org/

See website for : rearrangement reactions in organic chemistry | ppt organic chemistry reactions |wittig reaction |wittig synthesis | msc organic chemistry | benzilic acid rearrangement | wittig olefination synthesis reaction | wagner meerwein rearrangement | organic chemistry class 11organic