Tandem Rh(ii)-catalyzed 1,3-acyloxy migration/intermolecular [2 + 2] cycloaddition of electron-deficient propargylic esters with alkenes and alkynes†

Description

Zurong Xu and co-authors report a 2024 chemistry method that builds ring shaped molecules in a single pot. A known route turns a class of starting esters into reactive allenes through a shift of an acyloxy group, helped by a metal catalyst. That route worked mainly for esters rich in electrons, and the follow up reactions were few. The team use a rhodium catalyst to run the shift on esters that are poor in electrons instead.

After the shift, the allene joins with simple alkenes or alkynes to close a four membered ring. Many useful ring products with a double bond on the side can be made this way. Tests showed the allene is the key middle step. A formyl group at the end of the starting ester proved crucial, and teamwork between the ester and the catalyst's ligand seems to drive the reaction.

Catalog record

Source: https://europepmc.org/articles/PMC11587885