Reddy Mandapati Bhargava, Prasanth Kesavan, Anandhan Ramasamy
Department of Organic Chemistry, University of Madras, Chennai-600025, Tamilnadu, India.
Org Lett. 2022 May 27;24(20):3674-3679. doi: 10.1021/acs.orglett.2c01296. Epub 2022 May 12.
We report a controlled radical cyclization cascade of isoquinoline-1,3,4(2)-triones, 3-hydroxyisoindolin-1-ones, and phthalimides from -alkynylated benzamides by metal-free photoredox catalyzed amidyl N-centered radical addition to the C-C triple bond using the proton-coupled electron transfer (PCET) process under mild reaction conditions. A time tunable synthesis of 3-hydroxyisoindolin-1-ones and phthalimides via β-carbonyl-C(sp) bond cleavage was also achieved under visible light irradiation. A mechanistic rationale for the radical cyclization cascade is supported by various control and quenching experiments as well as EPR studies.
我们报道了在温和反应条件下，通过无金属光氧化还原催化的质子耦合电子转移（PCET）过程，将酰胺基 N 中心自由基加成到 C-C 三键上，实现了从 α-炔基苯甲酰胺可控的异喹啉-1,3,4(2)-三酮、3-羟基异吲哚啉-1-酮和邻苯二甲酰亚胺的自由基环化串联反应。在可见光照射下，还通过 β-羰基-C(sp)键裂解实现了 3-羟基异吲哚啉-1-酮和邻苯二甲酰亚胺的时间可调合成。各种控制和猝灭实验以及电子顺磁共振（EPR）研究支持了自由基环化串联反应的机理原理。
