PubReading [76] - The Catalytic Asymmetric Intermolecular Prins Reaction - D. Díaz-Oviedo, R. Maji, and B. List

Despite their significant potential, catalytic asymmetric reactions of olefins with formaldehyde are rare and metal-free approaches have not been previously disclosed. Here we describe an enantioselective intermolecular Prins reaction of styrenes and paraformaldehyde to form 1,3-dioxanes, using confined imino-imidodiphosphate (iIDP) Brønsted acid catalysts. Isotope labeling experiments and computations suggest a concerted, highly asynchronous addition of an acid-activated formaldehyde oligomer to the olefin. The enantioenriched 1,3-dioxanes can be transformed into the corresponding optically active 1,3-diols, which are valuable synthetic building blocks. - https://doi.org/10.1021/jacs.1c10245 - 2021