Metal catalyst-free N-allylation/alkylation of imidazole and benzimidazole with Morita-Baylis-Hillman (MBH) alcohols and acetates

A highly & alpha;-regioselective N-nucleophilic allylic substitution of cyclic MBH alcohols and acetates with imidazole or benzimidazole, in toluene at reflux with an azeotropic distillation, was successfully carried out with no catalysts or additives, affording the corresponding N-substituted imidazole derivatives in good yields. On the other hand, in refluxing toluene or methanol, the aza-Michael addition of imidazole onto acyclic MBH alcohols was performed using DABCO as an additive, leading to the corresponding 1,4 adducts in 70-84% yields.

Automated summary

A highly α-regioselective N-nucleophilic allylic substitution reaction was conducted between cyclic MBH alcohols or acetates and imidazole or benzimidazole, using toluene as solvent and azeotropic distillation at reflux, resulting in good yields of N-substituted imidazole derivatives in the absence of catalysts or additives. On the other hand, the aza-Michael addition reaction of imidazole onto acyclic MBH alcohols was performed in refluxing toluene or methanol, with the presence of DABCO as an additive, leading to 1,4 adducts in yields of 70-84%.