Melder JJ,
Heldner ML,
Kugler R,
Ziegenhagen LA,
Rominger F,
Rudolph M,
Hashmi AS. K.
*
Heidelberg University, Germany
Easy Access to Functionalized Indolines and Tetrahydroquinolines via a Photochemical Cascade Cyclization Reaction.
J. Am. Chem. Soc. 2024;
146: 14521-14527
DOI:
10.1021/jacs.4c00962
Key words
gold catalysis - photochemical - domino process - radical addition - indolines - tetrahydroquinolines
Significance
The authors report the synthesis of indolines and tetrahydroquinolines through the coupling of an N-aryl-N-allylamine and a bromoalkane in a gold-catalyzed photochemical domino reaction. Using this method, they were able to synthesis a biologically active compound precursor. The reaction is amenable to a variety of electron donating and withdrawing groups on the aromatic ring.
Comment
The authors show that the inclusion of Na-ascorbate increases the yield from 40% to 81%. This additive has been shown to increase the effectiveness of the gold photocatalyst used. They hypothesize that after radical addition to the allyl amine the intermediate can either cyclize in a radical process and then be oxidized or can be oxidized and then cyclize through an EAS reaction.
