Visible‐Light‐Driven Cyclizations

Abstract

In recent years, the interest in developing cyclizations promoted by visible light has been gaining a lot of attention due to its sustainability aspect. In this review, we summarize the most important advances in this period by describing the methods used to generate different ring sizes, while focusing on the mechanistic details of these reactions

Visible Light-Induced Radical Cascade Difluoromethylation/Cyclization of Unactivated Alkenes: Access to CF2H-Substituted Polycyclic Imidazoles

“…17 Currently, the strategy of photocatalytic radical cascade cyclization for the synthesis of heterocyclic compounds has emerged as a promising methodology due to its efficiency and environmental friendliness. 18 Therefore, the development of protocols for visible lightinduced radical cascade difluoromethylation/cyclization with [Ph 3 PCF 2 H] + Br − to synthesize CF 2 H-functionalized N-heterocyclic compounds is of great importance. 19 The benzimidazole core is widely recognized as an important pharmacophore with biological activity.…”

Photo‐Induced Difluoromethylation‐Cyclization of Indoles Using Tetrazole Sulfone Reagent Under Visible Light

“…[4] The cascade radical addition/cyclization of N-alkene tethered indoles has been proved as a convenient route towards the polycyclic indoles. [5] A viarety of radical species such as trichloromethyl radical (•CCl 3 ), [6] sulfonyl radical (Ts•), [7] phosphite radical(•PO(OEt) 2 ) [8] were explored to construct the pyrrolo [1,2-a]indoles under copper, [9] palladium, [10] nickel, [11] silver, [12] metal-free, [13] peroxides, [6] electrochemical synthesis [14] and photocatalysis. [8a,15] In most cases, an electron-withdrawing group at the C3 position was required.…”