Vinyl-1,2,4-oxadiazoles Behave as Nucleophilic Partners in Morita–Baylis–Hillman Reactions

We describe that vinyl-oxadiazoles
function as a new and efficient
nucleophilic partner for the Morita–Baylis–Hillman (MBH)
reaction. The reaction between 5-vinyl-3-aryl-1,2,4-oxadiazoles and
aromatic and aliphatic aldehydes, catalyzed by DABCO in the absence
of solvent, showed high efficiency to afford a new class of heterocyclic
MBH adducts with potential biological activity on yields up to 99%
and short reaction times. These synthetically attractive adducts bear
a heterocyclic scaffold of large pharmaceutical and commercial interest
associated with a plethora of biological effects and technological
applications. We also demonstrate their synthetic usefulness by a
photoinduced addition reaction to a polyfunctionalized amino alcohol.