Here is Sommelet-Hauser rearrangement definition with mechanism and example without doubt.
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what is Sommelet-Hauser rearrangement explain?
Sommelet-Hauser rearrangement is one of the thermal [2,3]-sigmatropic rearrangements, in which the benzylic quaternary ammonium salts are treated within the presence of a strong base like NaNH2, KNH2, as well as alkyl lithium to prepare the Substituted 3° benzylic amine.
Sommelet-Hauser rearrangement takes place in the presence of a strong base as well as aprotic solvents. The rearrangement can be done on substituted aromatic ring like benzene as well as a substituted heteroaromatic ring.
To point out the two competing reactions that can occur on the substrate under Sommelet-Hauser rearrangement reaction condition are as follow
- Hofmann elimination: when hydrogen atoms are present on alkyl groups attached to the nitrogen, elimination reaction can take under place those circumstances
- Stevens rearrangement: if there are cyclic quaternary ammonium salts that can give ring-expansion reaction.
Sommelet Hauser Rearrangement Mechanism:
In the mechanism Sommelet-Hauser rearrangement first step is the formation of nitrogen yield intermediate, which is generated from benzylic quaternary ammonium salts by removing acidic proton using a strong base. The next step is the sigmatropic rearrangement, and then benzylic amines will form as I have shown below image.
Applications of Sommelet-Hauser Rearrangement:
- Total synthesis of the potent antibiotic natural product streptonigrin.
- Synthesis of 4,7-disubstituted indoles from aryl sulfilimines.
- Potential herbicides 5-Tetrahydrophtalimide-substituted indolin-2(3H)-ones synthesis.
Related Reaction:
- Hofmann elimination
- Stevens rearrangement
- Claisen rearrangement
- Cope rearrangement
- Wittig rearrangement
- Oxy-Cope rearrangement
- aza-Wittig rearrangement
References :
- https://doi.org/10.1002/9780470638859.conrr591
- https://www.sciencedirect.com/topics/chemistry/sommelet-hauser-rearrangement
- https://pubs.acs.org/doi/10.1021/ja00884a015
My name is Pradip Sanjay W. I’m an organic chemist originally from Maharashtra, India. I have qualified UGC NET-JRF, GATE in chemical sciences and MH-SET exam for assistant professor. I’m currently pursuing my Ph.D. in organic chemistry at the Indian Institute of Technology Hyderabad, India.
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