Complete Catalytic Deoxygenation of CO2 into Formamidine Derivatives



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C1, seen them all: A catalytic transformation that uses CO2 as an oxygen-free C1 building block is presented. The reductive functionalization of CO2 is promoted by N-heterocyclic carbenes or guanidines as organocatalysts in the presence of amines and hydrosilanes. This diagonal strategy selectively affords benzimidazoles, quinazolinones, 3,4-dihydroquinazolines, formamidines, and their derivatives, directly from CO2 under mild conditions.