91Ó°ÊÓ

Secondary alcohols can be converted to ketones by oxidizing with acidified ${\mathbf{CrO}}_{\mathbf{3}}$Alcohols canbe converted into alkenes by treating with${\mathbf{POCl}}_{\mathbf{3}}$ in pyridine.A secondary alcohol can be converted to tertiary alcohol by oxidizing the alcohol to ketone followed by treatment with Grignard reagent.

(a)Cyclopentanone can be prepared from cyclopentanol by reacting cyclopentanol with ${\mathrm{CrO}}_3$and ${\mathrm{H}}_3{\mathrm{O}}^{+}$. The reaction can be given as:

Reaction (a)

(b)Cyclopentene can be prepared from cyclopentanone by reacting cyclopentanol with ${\mathrm{POCl}}_3$and pyridine. The reaction can be given as:

Reaction (b)

(c)1-Methylcyclopentanol can be prepared from cyclopentanol by reacting cyclopentanol in the presence of ${\mathrm{CrO}}_3$and ${\mathrm{H}}_3{\mathrm{O}}^{+}$to form cyclopentanone. This compound further reacts with ${\mathrm{CH}}_3\mathrm{MgBr}$and ${\mathrm{H}}_3{\mathrm{O}}^{+}$to form 1-Methylcyclopentanol. The reaction can be given as:

Reaction (c)

(d)The compound, trans-2-Methylcyclopentanol can be formed by reacting 1-Methylcyclopentanol with ${\mathrm{H}}_3{\mathrm{O}}^{+}$to form cyclopentene with methyl group as the substituent. This is further treated with ${\mathrm{BH}}_3$, THF, ${\mathrm{H}}_2{\mathrm{O}}_2$and ${}^{-}\mathrm{OH}$to form trans-2-Methylcyclopentanol. The reaction can be given as:

Reaction (d)