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Abstract Visible‐light photocatalysis has advanced as a versatile tool in organic synthesis. However, attaining precise stereocontrol in photocatalytic reactions has been a longstanding challenge due to undesired photochemical background reactions and the involvement of highly reactive radicals or radical ion intermediates generated under photocatalytic conditions. To address this problem and expand the synthetic utility of photocatalytic reactions, a number of innovative strategies, including mono‐ and dual‐catalytic approaches, have recently emerged. Of these, exploiting chiral organocatalysis, such as enamine catalysis, iminium‐ion catalysis, Brønsted acid/base catalysis, andN‐heterocyclic carbene catalysis, to induce chirality transfer of photocatalytic reactions has been widely explored. This Review aims to provide a current, comprehensive overview of asymmetric photocatalytic reactions enabled by chiral organocatalysts published through June 2021. The substrate scope, advantages, limitations, and proposed reaction mechanisms of each reaction are discussed. This review should serve as a reference for the development of visible‐light‐induced asymmetric photocatalysis and promote the improvement of the chemical reactivity and stereoselectivity of these reactions.
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Radical Reactivity of Thioimidates for Diversified Polymeric Amidines with Tunable Properties
Abstract The first reactions of thioimidates under radical‐mediated conditions are described along with the delineation of structural factors that impact radical reactivity and possible side reactions. Thioimidate‐containing copolymers with methylmethacrylate (MMA) are synthesized through radical‐mediated, chain‐growth polymerization. These materials serve as a synthetic branch point for facile conversion into amidines by treatment with a weak acid and an external amine. Our approach allows for more diverse amidine structures than have been previously reported in polymers. This chemistry also enables crosslinking to form novel hydrogels with finely tuned acid–base behavior. Subsequent examination of the acid–base properties revealed that these features are preserved across linear, soluble amidine polymers to cross‐linked amidine gel polymer architectures.
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- Award ID(s):
- 2404390
- PAR ID:
- 10634447
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 64
- Issue:
- 36
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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