${H_2}C\, - \,\,\mathop C\limits_{\mathop |\limits_D } H\, - \,\,\mathop C\limits_{\mathop |\limits_{C{H_3}} } H\, - \,\,C{H_3}\, + \,\,Br\,\, \to \,\,'X'\,\, + \,\,HBr$
$CH_3CH_2CH_2CH_2CH_2CH_3$ $(CH_3)_3 CCH_2CH_3$
$(CH_3)_2CHCH_2CH_2CH_3$ $(CH_3)_2CHCH(CH_3)_2$