Dynamic Kinetic Sensitization of beta-Dicarbonyl Compounds-Access to Medium-Sized Rings by De Mayo-Type Ring Expansion

Paulisch TO, Mai L, Strieth-Kalthoff F, James MJ, Henkel C, Guldi DM, Glorius F (2021)


Publication Type: Journal article

Publication year: 2021

Journal

DOI: 10.1002/anie.202112695

Abstract

Herein, we present a photocatalyzed two-carbon ring expansion of beta-dicarbonyl compounds with unactivated olefins that provides facile access to medium-sized rings. Selective sensitization of the substoichiometric enol tautomer enables reactivity of substrates incompatible with the classical De Mayo reaction conditions. Key to success is the identification of the metal-based sensitizer fac-[Ir(CF3-pmb)(3)], which can be excited using common near-visible LEDs, and possesses a high triplet excited state energy of 73.3 kcal mol(-1). This exactly falls in the range between the triplet energies of the enol and keto tautomer, thereby enabling a dynamic kinetic sensitization. Demonstrating the applicability of fac-[Ir(CF3-pmb)(3)] as a photocatalyst in organic synthesis for the first time, we describe a two-step photocycloaddition-ring-opening cascade with beta-ketoesters, -diketones, and -ketoamides. The mechanism has been corroborated by time-resolved spectroscopy, as well as further experimental and computational studies.

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APA:

Paulisch, T.O., Mai, L., Strieth-Kalthoff, F., James, M.J., Henkel, C., Guldi, D.M., & Glorius, F. (2021). Dynamic Kinetic Sensitization of beta-Dicarbonyl Compounds-Access to Medium-Sized Rings by De Mayo-Type Ring Expansion. Angewandte Chemie International Edition. https://dx.doi.org/10.1002/anie.202112695

MLA:

Paulisch, Tiffany O., et al. "Dynamic Kinetic Sensitization of beta-Dicarbonyl Compounds-Access to Medium-Sized Rings by De Mayo-Type Ring Expansion." Angewandte Chemie International Edition (2021).

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