Visible light-induced radical cascade acylmethylation/cyclization of 2-(allyloxy)arylaldehydes with α-bromo ketones: access to cyclic 1,5-dicarbonyl-containing chroman-4-one skeletons

Abstract

A novel photocatalytic protocol for effective and efficient synthesis of cyclic 1,5-diketone containing chroman-4-one skeletons in moderate to good yields via radical cascade acylmethylation/cyclization of 2-(allyloxy)arylaldehydes with a-bromo ketones has...

Catalyst-controlled and visible light-induced acylmethylation and bromoacylmethylation of Morita–Baylis–Hillman acetates with α-bromo ketones: access to highly functionalized 1,5-dicarbonyl compounds

“…On the basis of the above control experiment results and related literature reports, 21 g ,23 two possible pathways for the preparation of products 3 and 4 are described in Scheme 6. First, irradiation with visible light induced an excited state rose bengal*, which is then reductively quenched by the sacrificial electron donor TIPA to afford rose bengal˙ − (path a) or induced a single electron transfer (SET) to the photocatalyst fac -Ir(ppy) 3 , resulting in the excited-state fac -Ir(ppy) 3 * (path b).…”