A Cs 2 CO 3 -mediated [2 + 1] cycloaddition of benzofuran-derived azadienes (BDAs) with bromomalonate by using a dearomatization strategy has been developed. Through this process, BDAs serve as a potential 2-atom synthon in the construction of a range of functionalized spirocyclopropane derivatives, such as spirobenzofuran-2-cyclopropanes and spiroindane-2-cyclopropanes.

An efficient copper-catalyzed cascade annulation of o-hydroxyphenyl propargylamines and pyrazolin-5-ones is described. This methodology leads to the rapid assembly of a series of valuable pyrano­[2,3-c]­pyrazoles with good yields across a wide range of substrates in a simple fashion. This novel reaction involves the formation of alkynyl ortho-quinone methides, a 1,4-conjugate addition, and a subsequent 6-endo cyclization process. The mechanistic elucidation is well supported by control experiment and literature precedents.

A rapid and highly efficient 1,3‐dipolar [3 + 2] cycloaddition of nonstabilized azomethine ylides generated in situ with benzo[b]thiophene 1,1‐dioxides as the dipolarophiles has been developed. The efficient method affords tricyclic pyrrolidine‐fused benzo[b]thiophene 1,1‐dioxide derivatives in high to excellent yields (up to 99%) with excellent diastereoselectivities (up to >25:1 dr) under mild reaction conditions. The structure of a typical product was confirmed by X‐ray crystallography.