Any time we have a Grignard reagent and a primary haloalkane, we will see a substitution reaction, identical to an reaction. In this case, the Grignard can easily attack the haloalkane as the bromine leaves to create hexene.

The carbons on the epoxide compound experience a slightly positive charge. As a result, a Gringard reagent can easily attack the less substituted side of the epoxide to break the ring and to form a six membered carbon chain. is used to protonate the negatively charged oxygen atom.

Grignard reagents are known for their ability to readily attack carbonyls at the point of their carbons. However, Grignard reagents do not work in the presence of protic solvents. Rather than reacting with the desired molecule, the Grignard is so unstable that it will readily accept a proton from a protic solvent. The Grignard then becomes inert and no reaction ensues with the desired molecule.

The reaction between magnesium and an alkyl halide in anhydrous ether results in a Grignard reagent.

An organolithium would result from the same process, but the magnesium would need to be replaced by two equivalents of lithium. Alcohols are products of reactions between a Grignard reagent and a carbonyl.