Reddy MB, Prasanth K, Anandhan R. Controlled Photochemical Synthesis of Substituted Isoquinoline-1,3,4(2
H)-triones, 3-Hydroxyisoindolin-1-ones, and Phthalimides via Amidyl Radical Cyclization Cascade.
Org Lett 2022;
24:3674-3679. [PMID:
35549291 DOI:
10.1021/acs.orglett.2c01296]
[Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report a controlled radical cyclization cascade of isoquinoline-1,3,4(2H)-triones, 3-hydroxyisoindolin-1-ones, and phthalimides from o-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(sp3) 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.
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