The reaction of 1-bromo-2-methylpropane (isobutyl bromide), [tex](CH_3)_2CHCH_2Br[/tex], with [tex]Mg[/tex], and [tex]Et_2O[/tex] results in the formation of an adduct of formula [tex](CH_3)_2CHCH_2MgBr[/tex] known as grignard reagent, an organometallic reagent, which on reacting with [tex]H_3O^{+}[/tex] results in the formation of isobutane.
The reaction is shown in the image.