Studies toward the total synthesis of the variolins: rapid entry to the core structure

The pyrido[3′,2′:4,5]pyrrolo[1,2-c]pyrimidine core structure of the variolins has been synthesized in three steps from commercially available materials. The key reaction involves the deoxygenation and concomitant cyclization of a triarylmethanol using the combination of triethylsilane and trifluoroacetic acid. Introduction of amine functionality as required for the natural products has been achieved in two steps.