Red light-induced conjugation of amines through amide bond formation triggered via photooxidation of 3-acylindolizines

Abstract

The development of a conjugation method initiated by irradiation of long-wavelength light (>500 nm) to prepare densely functionalized molecules while avoiding undesired photodegradation has attracted considerable attention. Here we show an amide bond formation method based on the photoreaction of 3-acylindolizines in the presence of amines triggered via red-light irradiation. Photooxidation of 3-acylindolizines using a catalytic amount of a photosensitizer and red light-emitting diodes (660 nm) affords the corresponding conjugated amides in nearly quantitative yields within <5 min. This transformation can be performed in aqueous organic solvents and is applicable to diverse aliphatic amines with various functional groups, including the moieties responsive to short-wavelength light.

Clickable bisreactive small gold nanoclusters for preparing multifunctionalized nanomaterials: application to photouncaging of an anticancer molecule

“…[35][36][37][38][39][40] We have also developed an uncaging system based on the photooxidation of indolizine cores (Scheme S1 †). [41][42][43] This system allows for a rapid release of caged molecules with the help of singlet oxygen generated by biopermeable red light irradiation in the presence of a separately added PS. This enables efficient uncaging of carboxylic acids or alcohols.…”