Preparation of cycloalkanes

preparation of cycloalkane

1. Preparation of cycloalkanes

2. It is regarded as internal wurtz reaction

3. When dihlogen derivative of paraffin are treated with zinc or sodium, corresponding cyclopropane is formed. In dihalogen atoms two halogens are apart in 1: 6 then rings wont form. But it undergoes wurtz reaction to form long chain alkanes.

4. When calcium or barium salt of dicarboxylic acid is distilled a ketone is formed Barium adipate Cyclopentanone

5. Cyclic ketones can be directly conver ted into cyclo alkanes by clemmenson reduction Cyclohexanone Cyclohexane

6. By using acetoacetic ester, it is possible to prepare rings containing 3,5,6 and 7 carbon atoms but not four; all attempts to prepare a four membered ring result in the formation of dihydropyran derivative

7. Certain cyclic ketones obtained by Dieckmann reaction. This reaction is intramolecular acetoacetic ester condensation [ claisen condensation]. This raction is carried out by treating the esters of adipic acid with sodium.

8. Hydroxy cyclic compound may be prepared by reducing certain diketnes with magnesium amalgam; the reaction is pinacol reduction. Heptane-2:6-dione 1:2 dimethyl cyclo pentane 1;2 diol

9. Diel’s alder reaction