Question

Q6. How will you synthesis Cycloalkanes by the following methods. Write a detailed stepwise mechanism for each. a) Dehalogenation of ,-dihalides b) Catalytic hydrogenation of cyclic alkenes c) Reduction of cyclic ketones d) Diels Alder Reaction e) Simonsmith reactions

Answer 1

Simonsmith reactions

Answer 2

synthesis Cycloalkanes by(e) Simonsmith reactions

Explanation:

1.Simmons-Smith reaction is an asymmetric reaction in which a carbenoid adds to an alkene or alkyne to form a cyclopropane. It is an essential reaction involving an organozinc reagent.

2.The reaction is typically conducted using diiodomethane in combination with metallic zinc and copper (Zn(Cu)). The iodomethyl zinc iodide is usually prepared using Zn activated with Cu.

3.Mechanism:

a.both the new bond are formed simutaneously at C=C double bond.

b.Iodide leaves the carbon then it undergoes electrophilic addition.

c.electrons from the nucleophilic C-Zn bond formthe other C-C bond.

4.The Simmons-Smith reaction has a considerable advantage over other cyclopropanation methods. It does not require the use of highly hazardous diazomethane.

5.Besides, the reaction has a broad functional group tolerance, including with alkynes, carbonyls, alcohols, ethers, and others.