CH610B Sophomore Organic II

Dr. Brian Pagenkopf

What do we need to know about these organometallic reagents?

1) all of them are strong bases and readily react with acidic proton sources such as water and carboxylic acids.

2) When you simply need a really strong base, use n-BuLi. n-BuLi is a good reagent to deprotonate diisopropyl amine (to make lithium diisopropyl amine, LDA) and terminal alkynes. Alkyl lithium reagents will add to carboxylic acids, for every other addition reaction use a Grignard or Gilman reagent.

3) Organomagnesium (Grignard) reagents love to react with aldehydes, ketones and esters to form new carbon-carbon bonds. When given a choice, always use Grignard reagents for addition reactions to aldehydes, ketones or esters.

4) Gilman reagents undergo S_N2 reactions with carbon-halogen bonds, even with sp² hybridized carbons – and we didn’t see THAT last semester!! They are also excellent for conjugate additions, to be discussed later.

5) Both Grignard and Gilman reagents react with epoxides. Don’t use organolithium reagents to open epoxides because they are too basic