In 1900, a French chemist, Victor Grignard, discovered that haloalkanes reacted with magnesium in diethyl ether solution. His discovery led to the whole field of organometalic reagents which have provided modern organic chemists with one of their most versatile tools. As a result of his pioneering work, Grignard received the Nobel Prize in Chemistry in 1912.
Below is my rendition of a 'Grignard clock' which summarizes some of the more important molecular transformations that can be realized by reacting phenylmagnesiumbromide with the appropriate reagents. Keep in mind, that these Grignard reactions are not limited to arenes, but work equally well for alkanes as well. It might be a rewarding experience for you to familiarize yourself with the specific reaction conditions that would produce each of the following products: