Solve this following

$\mathrm{HCHO}+\mathrm{PhCH}\left(\mathrm{CH}_{3}\right) \mathrm{CH}_{2} \mathrm{MgX}$

$\mathrm{PhCOCH}_{2} \mathrm{CH}_{3}+\mathrm{CH}_{3} \mathrm{MgX}$

$\mathrm{PhCOCH}_{3}+\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{MgX}$

$\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{COCH}_{3}+\mathrm{PhMgX}$