Photocatalytic Regio‐ and Site‐Selective Alkylamination of Coumarins: Access to 3‐Amino‐ and 4‐Amino Dihydrocoumarins

Abstract

Functionalized dihydrocoumarins, including 3‐amino‐ and 4‐amino dihydrocoumarins serving as α‐ and β‐amino acid derivatives, have been synthesized using one‐step site‐ and regioselective alkylamination from coumarins. This conversion offers 35 examples in 24% to 81% yields.

Syntheses, reactivity, and biological applications of coumarins

“…It is worth to mention another photocatalytic approach employed for the synthesis of variously substituted dihydrocoumarins ( 146 ) starting from coumarins substituted with an EWG at position 3 ( 143 , Scheme 7 — path e ). The protocol reported by Xia and collaborators employed 3-CN, 3-acetyl, or 3-Bz substituted coumarins (as 143 ) that were subsequently transformed into 4-amino dihydrocoumarins ( 146 ) via an alkylamination reaction at room temperature in EtOAc using [Ir(dF-(CF 3 )ppy) 2 (dtbbpy)](PF 6 ) ( 145 ) as the photosensitizer ( Jiang Y. S. et al, 2023 ).…”

Photocatalytic Multicomponent 1,n-Carboimination with Alkyl Iodides and O-Benzoyl Oxime through EnT and XAT Processes

“…These challenges restrict the broader utilization of bifunctionalized reagents despite their high efficiency in introducing two distinct functional groups. In recent studies, several alkylimination transformations utilizing difunctional reagents derived from benzophenone oxime esters have been documented . These reactions have successfully produced a diverse range of difunctional products from alkenes.…”