Organocatalytic cascade reaction for the synthesis of polycylic compounds utilizing Trienamine activation

Abstract

We report an Aminocatalytic privileged Diversity-Oriented Synthesis (ApDOS) strategy via trienamine catalysis for the construction of diverse and complex thiopyrans-piperidone fused rings through a thia-Diels–Alder/nucleophilic ring closing sequence by using dithioamides as activated heterodienophiles. Following this strategy, a super cascade reaction to assemble nine fused rings can be achieved by employing a bis-dithioamide. Additionally, by linking an indole moiety on the dithioamide, a Pictet-Spengler type reaction can be promoted once the cascade sequence has been achieved, leading to more complex penta- hexa- and heptacyclic fused ring derivatives in a one-pot process. This investigation, open new perspectives for the synthesis of a new class of complex and diverse thiopyrans, which contribute to populate new relevant regions in the chemical space.