Organocatalytic Thioesterification of a Conjugated α,β-Unsaturated Dialdehyde.

Thioesterification of (2E,2'E)-3,3'-(1,4-phenylene)diacrylaldehyde with thiols has been performed using a bulky N-heterocyclic carbene (NHC) as an organocatalyst. This metal-free protocol enables efficient synthesis of new mono and difunctional acrolein derivatives in high isolated yields under mild conditions. Importantly, the reaction proceeds in the absence of external additives or oxidants, and requires only low organocatalyst loadings, thereby facilitating the straightforward isolation of structurally defined sulfur-containing acrolein derivatives in both symmetric and asymmetric forms. The resulting functional acrolein derivatives are the hitherto underexplored class of functional building blocks with promising potential for biomedical materials, including drug delivery systems and other biomaterials applications.