DBU-promoted synthesis of novel heterocyclic [4.3.3] propellanes from α‑cyanoketones and cyclic α-diketones

Abstract

An effective base-catalyzed Knoevenagel, Michael and intramolecular/Paal-Knorr cyclization strategy for the construction of heterocyclic [4.3.3] tetrahydro epoxyetheno benzo-furan propellanes (TEBFs) from cyclic α-diketones and α‑cyanoketones is reported through single-step reaction. The reaction proceeds under mild reaction conditions and shows excellent chemo and distereoselectivity in the absence of any external transition metal and ligands. The one-pot two-component procedure also shows the merits of straightforward reaction conditions, simple operation, using available feedstock, wide substrate scope, and high atom and step economy. This reaction provides facile access to highly substituted fused tetrahydro furo-furan propellanes, which can be used in the field of chemical and pharmaceutical research.