Organometallic reagents as bases

These reagents are very strong bases (pKa’s of saturated hydrocarbons range are around 50). Although not usually done with Grignard reagents, organolithium reagents can be used as strong bases. Both Grignard reagents and organolithium reagents react with water to form the corresponding hydrocarbon. This is why so much care is needed to insure dry glassware and solvents when working with organometallic reagents.

In fact, the reaction of Grignard reagents and organolithium reagents with water can be exploited to convert alkyl halides into the corresponding hydrocarbon (illustrated below). The halogen is converted to an organometallic reagent and then subsequently reacted with water to form an alkane.