Studies of Reversible Conjugate Additions

Abstract Benzalcyanoacetamides were designed and synthesized as reversible thiol conjugate addition acceptors. These thia‐conjugate additions can rapidly and reversibly achieve equilibrium under aqueous conditions at neutral pH. Kinetic studies show that electron‐withdrawing groups at the 4‐position of the phenyl ring of the benzalcyanoacetamides promote the conjugate addition at equilibrium. Dynamic thiol exchange of these conjugate acceptors is faster than singly activated α,β‐unsaturated carbonyl compounds. These thia‐conjugate additions can be assembled as potentially useful components in dynamic combinatorial chemistry.