Manganese-Catalyzed Multicomponent Synthesis of Pyrimidines from Alcohols and Amidines

Abstract

The development of catalytic reactions for synthesizing different compounds from alcohols to save fossil carbon feedstock and reduce CO₂ emissions is of high importance. Replacing rare noble metals with abundantly available 3d metals is equally important. We report a manganese-complex-catalyzed multicomponent synthesis of pyrimidines from amidines and up to three alcohols. Our reaction proceeds through condensation and dehydrogenation steps, permitting selective C-C and C-N bond formations. β-Alkylation reactions are used to multiply alkylate secondary alcohols with two different primary alcohols to synthesize fully substituted pyrimidines in a one-pot process. Our PN₅ P-Mn-pincer complexes efficiently catalyze this multicomponent process. A comparison of our manganese catalysts with related cobalt catalysts indicates that manganese shows a reactivity similar to that of iridium but not cobalt. This analogy could be used to develop further (de)hydrogenation reactions with manganese complexes.

Keywords: borrowing-hydrogen reactions; dehydrogenative coupling; maganese; pincer complexes; pyrimidines.