When keto compound react with ${\mathrm{CH}}_3\mathrm{Mg}/{\mathrm{H}}_2\mathrm{O}$ then  ${\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{C}\left({\mathrm{CH}}_3\right)\left(\mathrm{OH}\right)$ is formed as product  when the reaction further proceeded in the presence of ${\mathrm{H}}_3{\mathrm{PO}}_4/{\mathrm{B}}_2{\mathrm{H}}_6/\mathrm{NaOH}$ then the reaction undergoes in ${\mathrm{SN}}_2$ reaction finally when oxidation takes place then in the presence of $\mathrm{PCC}$ then