The reactions of alkyllithiums with ketones and thioketones proceed in fundamentally different ways. Whereas alkyllithiums add to the carbonyl carbon of ketones to give tertiary alcohols, the reaction with thioketones proceeds to give secondary thiols by reduction of the CS group. Transition states for the addition and reduction reactions of acetone and thioacetone in ethereal solution have been located and the computed activation free energies are in agreement with the observed behavior of ketones and thioketones in reactions with alkyllithiums.

The reactions of adamantanethione (1) with several Grignard reagents (MeMgCl, n-BuMgCl, and t-BuMgCl) have been investigated. In contrast to analogous reactions with ketones, there is no evidence of addition to the CS carbon of 1. Rather, reaction of 1 with n-BuMgCl or t-BuMgCl affords 2-adamantanethiol as the major product along with minor amounts of sulfides and an episulfide. Reactions of 1 with MeMgCl are very slow and afford a variety of products as a result of secondary reactions.