Phthalimide and Its Derivatives

Coyle, J. D.

doi:10.1007/978-1-4613-2681-6_4

Cited by 28 publications

(3 citation statements)

References 79 publications

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“…Early studies by Kanaoka and Coyle showed that phthalimides participate in a number of different types of interesting SET-photochemical reactions. As a consequence of high singlet and triplet excited-state reduction potentials ( E 1 S1 (−) = 2.3 V; E 1 T1 (−) = 1.6 V), these substances participate in SET-promoted excited-state reactions when paired with appropriate electron donors.…”

Section: Phthalimide Single-electron Transfer Photochemistrymentioning

confidence: 99%

Studies Leading to the Development of a Single-Electron Transfer (SET) Photochemical Strategy for Syntheses of Macrocyclic Polyethers, Polythioethers, and Polyamides

2010

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Organic photochemists began to recognize in the 1970s that a new mechanistic pathway involving excited-state single-electron transfer (SET) could be used to drive unique photochemical reactions. Arnold's seminal studies demonstrated that SET photochemical reactions proceed by way of ion radical intermediates, the properties of which govern the nature of the ensuing reaction pathways. Thus, in contrast to classical photochemical reactions, SET-promoted excited-state processes are controlled by the nature and rates of secondary reactions of intermediate ion radicals. In this Account, we discuss our work in harnessing SET pathways for photochemical synthesis, focusing on the successful production of macrocyclic polyethers, polythioethers, and polyamides. One major thrust of our studies in SET photochemistry has been to develop new, efficient reactions that can be used for the preparation of important natural and non-natural substances. Our efforts with α-silyl donor-tethered phthalimides and naphthalimides have led to the discovery of efficient photochemical processes in which excited-state SET is followed by regioselective formation of carbon-centered radicals. The radical formation takes place through nucleophile-assisted desilylation of intermediate α-silyl-substituted ether-, thioether-, amine-, and amide-centered cation radicals. Early laser flash photolysis studies demonstrated that the rates of methanol- and water-promoted bimolecular desilylations of cation radicals (derived from α-silyl electron donors) exceeded the rates of other cation radical α-fragmentation processes, such as α-deprotonation. In addition, mechanistic analyses of a variety of SET-promoted photocyclization reactions of α-silyl polydonor-linked phthalimides and naphthalimides showed that the chemical and quantum efficiencies of the processes are highly dependent on the lengths and types of the chains connecting the imide acceptor and α-silyl electron donor centers. We also observed that reaction efficiencies are controlled by the rates of desilylation at the α-silyl donor cation radical moieties in intermediate zwitterionic biradicals that are formed by either direct excited-state intramolecular SET or by SET between the donor sites in the intervening chains. It is important to note that knowledge about how these factors govern product yields, regiochemical selectivities, and quantum efficiencies was crucial for the design of synthetically useful photochemical reactions of linked polydonor-acceptor substrates. The fruits of these insights are exemplified by synthetic applications in the concise preparation of cyclic peptide mimics, crown ethers and their lariat- and bis-analogs, and substances that serve as fluorescence sensors for important heavy metal cations.

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Section: Phthalimide Single-electron Transfer Photochemistrymentioning

confidence: 99%

Studies Leading to the Development of a Single-Electron Transfer (SET) Photochemical Strategy for Syntheses of Macrocyclic Polyethers, Polythioethers, and Polyamides

2010

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“…Like their aromatic ketone counterparts, phthalimide excited states participate in hydrogen atom abstraction. Numerous examples of photochemical processes, initiated in this manner, have been uncovered in investigations of phthalimide photochemistry . In addition, irradiation of N -alkylphthalimides leads to preferential γ-hydrogen atom abstraction as part of N-heterocyclic ring-forming reactions. , Kanaoka's pioneering work in this area led to the discovery of another interesting excited-state property of phthalimides.…”

Section: Introductionmentioning

confidence: 99%

The Synthetic Potential of Phthalimide SET Photochemistry

2001

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The authors' studies in the area of phthalimide photochemistry are discussed in the context of the development of new methods for N-heterocycle synthesis. Emphasis is given to reactions which are initiated by both intermolecular and intramolecular SET from silicon-containing electron donors to excited states of phthalimides and related maleimides and conjugated imides. The photoaddition and photocyclization processes which ensue follow mechanistic pathways, in which efficient desilylation of initially formed radical cation occurs to generate radical pair and biradical intermediates that serve as precursors of the products. Several examples that demonstrate the preparative potential of these reactions are presented. These are taken from the authors' investigations of (1) phthalimido-alkylsilane photocyclization reactions, (2) azomethine ylide-forming excited-state processes of N-(trimethylsilylmethyl)phthalimide, and (3) photoaddition and photocyclization reactions of phthalimide alpha-silyl ether, thioether, amine, and amide systems.

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“…? 1.6 V) [21][22][23] that have appropriate reduction potentials. In addition, desilylation of benzyl silane radical cations should take place rapidly to form benzyl radicals that can undergo C-C bond forming reactions.…”

Section: Introductionmentioning

confidence: 99%

A strategy for the preparation of cyclic polyarenes based on single electron transfer-promoted photocyclization reactions

et al. 2011

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Single electron transfer (SET)-promoted photocyclization reactions of substrates comprised of benzylsilane tethered to phthalimides were subjected to an exploratory study in order to probe a new approach for the preparation of cyclic polyarenes. The results show that UV irradiation of the substrates leads to efficient photochemical reactions that are initiated by SET from benzylsilane moieties to the excited phthalimide acceptor. Ensuing desilylation reactions of the benzylsilane cation radical moieties in the intermediate zwitterionic biradicals and proton transfer gives biradical precursors of the cyclic polyarene products. The observations made in this effort suggests that SET photochemical methods, which have been employed earlier to generate cyclic poly-ethers, -thioethers and -amides, serve as a useful method to access potentially interesting macrocyclic targets.

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Phthalimide and Its Derivatives

Cited by 28 publications

References 79 publications

Studies Leading to the Development of a Single-Electron Transfer (SET) Photochemical Strategy for Syntheses of Macrocyclic Polyethers, Polythioethers, and Polyamides

Studies Leading to the Development of a Single-Electron Transfer (SET) Photochemical Strategy for Syntheses of Macrocyclic Polyethers, Polythioethers, and Polyamides

The Synthetic Potential of Phthalimide SET Photochemistry

A strategy for the preparation of cyclic polyarenes based on single electron transfer-promoted photocyclization reactions

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