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Patrick S. Mariano - One of the best experts on this subject based on the ideXlab platform.
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direct and indirect single electron transfer set photochemical approaches for the preparation of novel phthalimide and naphthalimide based lariat type crown ethers
Beilstein Journal of Organic Chemistry, 2014Co-Authors: Patrick S. Mariano, Ung Chan YoonAbstract:In this review, we describe direct and indirect photochemical approaches that have been developed for the preparation of phthalimide- and naphthalimide-based, lariat-type crown ethers. The direct route utilizes a strategy in which nitrogen-linked side chains containing polyethoxy-tethered Phthalimides and naPhthalimides, possessing terminal α-trialkylsilyl groups, are synthesized utilizing concise routes and UV-irradiation to form macrocyclic ring systems. In contrast, the indirect route developed for the synthesis of lariat-type crown ethers employs sequences in which SET-promoted macrocyclization reactions of α-trialkylsilyl-terminated, polyethoxy-tethered Phthalimides and naPhthalimides are followed by a side chain introduction through substitution reactions at the amidol centers in the macrocyclic ethers. The combined observations made in these investigations demonstrate the unique features of SET-promoted photocyclization reactions that make them well-suited for the use in the synthesis of functionalized crown ethers. In addition, while some limitations exist for the general use of SET-photochemical reactions in large-scale organic synthesis, important characteristics of the photoinduced macrocyclization reactions make them applicable to unique situations in which high temporal and spatial control is required.
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A strategy for the preparation of cyclic polyarenes based on single electron transfer-promoted photocyclization reactions
Research on Chemical Intermediates, 2012Co-Authors: Hea Jung Park, Byeol Na Park, Ung Chan Yoon, Jung Hei Choi, Patrick S. MarianoAbstract: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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A strategy for the preparation of cyclic polyarenes based on single electron transfer-promoted photocyclization reactions
Research on Chemical Intermediates, 2012Co-Authors: Hea Jung Park, Byeol Na Park, Ung Chan Yoon, Jung Hei Choi, Patrick S. MarianoAbstract: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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Exploratory Study of Photocyclization Reactions of N‐( Trimethylsilylmethylthioalkyl)Phthalimides.
ChemInform, 2010Co-Authors: Ung Chan Yoon, Sangjin Lee, Kyung Ja Lee, Sung Ju Cho, Chan Woo Lee, Patrick S. MarianoAbstract:Studies have been conducted to explore single electron transfer (SET) induced photocyclization reactions of N-(trimethylsilylmethylthioalkyl)Phthalimides (alkyl=ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl). Photocyclizations occur in methanol in modest to high yields to produce cyclized products in which phthalimide carbonyl carbon is bonded to the carbon of side chain in place of the trimethylsilyl group. Mechanism for these photocyclizations involving intramolecular SET from sulfur in the -silylmethylthioalkyl groups to the singlet excited state phthalimide moieties followed by desilylation of the intermediate -silylmethylthio cation radicals and cyclization by radical coupling is proposed. In contrast, photoreactions of N-(trimethylsilylmethylthioalkyl)Phthalimides in acetone follow different reaction routes to produce another cyclized products in which carbon-carbon bond formation takes place between the phthalimide carbonyl carbon and the carbon to silicon and sulfur atoms via triplet carbonyl hydrogen abstraction pathway. The normal singlet SET pathway dominates this triplet process for photoreactions of these substances in methanol while the triplet process dominates the singlet SET pathway for those in acetone. The efficient and regioselective cyclization reactions observed for photolyses in methanol represent synthetically useful processes for construction of medium and large ring heterocyclic compounds.
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a synthetic strategy for the preparation of cyclic peptide mimetics based on set promoted photocyclization processes
Journal of the American Chemical Society, 2003Co-Authors: Ung Chan Yoon, Ying Xue Jin, Chan Hyo Park, Jong Hoon Park, Charles F Campana, Xiaolu Cai, Eileen N Duesler, Patrick S. MarianoAbstract:A novel method for the synthesis of cyclic peptide analogues has been developed. The general approach relies on the use of SET-promoted photocyclization reactions of peptides that contain N-terminal Phthalimides as light absorbing electron acceptor moieties and C-terminal α-amidosilane or α-amidocarboxylate centers. Prototypical substrates are prepared by coupling preformed peptides with the acid chloride of N-phthalimidoglycine. Irradiation of these substrates results in the generation of cyclic peptide analogues in modest to good yields. The chemical efficiencies of these processes are not significantly affected by (1) the lengths of the peptide chains separating the phthalimide and α-amidosilane or α-amidocarboxylate centers and (2) the nature of the penultimate cation radical α-heterolytic fragmentation process (i.e., desilylation vs decarboxylation). An evaluation of the effects of N-alkyl substitution on the amide residues in the peptide chain showed that N-alkyl substitution does not have a major i...
Cheng-chu Zeng - One of the best experts on this subject based on the ideXlab platform.
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Electrochemical Dehydrogenative Imidation of N-Methyl-Substituted Benzylamines with Phthalimides for the Direct Synthesis of Phthalimide-Protected gem-Diamines
Organic Letters, 2018Co-Authors: Fei Lian, Kun Xu, Cheng-chu ZengAbstract:A general and green electrochemical dehydrogenative method for the imidation of N-methyl benzylamines with Phthalimides with excellent regioselectivities is reported for the first time. This operationally simple method offers a valuable tool to obtain structurally diverse phthalimide-protected gem-diamines.
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Electrochemical Dehydrogenative Imidation of N‑Methyl-Substituted Benzylamines with Phthalimides for the Direct Synthesis of Phthalimide-Protected gem-Diamines
2018Co-Authors: Fei Lian, Caocao Sun, Cheng-chu ZengAbstract:A general and green electrochemical dehydrogenative method for the imidation of N-methyl benzylamines with Phthalimides with excellent regioselectivities is reported for the first time. This operationally simple method offers a valuable tool to obtain structurally diverse phthalimide-protected gem-diamines
Ung Chan Yoon - One of the best experts on this subject based on the ideXlab platform.
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direct and indirect single electron transfer set photochemical approaches for the preparation of novel phthalimide and naphthalimide based lariat type crown ethers
Beilstein Journal of Organic Chemistry, 2014Co-Authors: Patrick S. Mariano, Ung Chan YoonAbstract:In this review, we describe direct and indirect photochemical approaches that have been developed for the preparation of phthalimide- and naphthalimide-based, lariat-type crown ethers. The direct route utilizes a strategy in which nitrogen-linked side chains containing polyethoxy-tethered Phthalimides and naPhthalimides, possessing terminal α-trialkylsilyl groups, are synthesized utilizing concise routes and UV-irradiation to form macrocyclic ring systems. In contrast, the indirect route developed for the synthesis of lariat-type crown ethers employs sequences in which SET-promoted macrocyclization reactions of α-trialkylsilyl-terminated, polyethoxy-tethered Phthalimides and naPhthalimides are followed by a side chain introduction through substitution reactions at the amidol centers in the macrocyclic ethers. The combined observations made in these investigations demonstrate the unique features of SET-promoted photocyclization reactions that make them well-suited for the use in the synthesis of functionalized crown ethers. In addition, while some limitations exist for the general use of SET-photochemical reactions in large-scale organic synthesis, important characteristics of the photoinduced macrocyclization reactions make them applicable to unique situations in which high temporal and spatial control is required.
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A strategy for the preparation of cyclic polyarenes based on single electron transfer-promoted photocyclization reactions
Research on Chemical Intermediates, 2012Co-Authors: Hea Jung Park, Byeol Na Park, Ung Chan Yoon, Jung Hei Choi, Patrick S. MarianoAbstract: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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A strategy for the preparation of cyclic polyarenes based on single electron transfer-promoted photocyclization reactions
Research on Chemical Intermediates, 2012Co-Authors: Hea Jung Park, Byeol Na Park, Ung Chan Yoon, Jung Hei Choi, Patrick S. MarianoAbstract: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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Exploratory Study of Photocyclization Reactions of N‐( Trimethylsilylmethylthioalkyl)Phthalimides.
ChemInform, 2010Co-Authors: Ung Chan Yoon, Sangjin Lee, Kyung Ja Lee, Sung Ju Cho, Chan Woo Lee, Patrick S. MarianoAbstract:Studies have been conducted to explore single electron transfer (SET) induced photocyclization reactions of N-(trimethylsilylmethylthioalkyl)Phthalimides (alkyl=ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl). Photocyclizations occur in methanol in modest to high yields to produce cyclized products in which phthalimide carbonyl carbon is bonded to the carbon of side chain in place of the trimethylsilyl group. Mechanism for these photocyclizations involving intramolecular SET from sulfur in the -silylmethylthioalkyl groups to the singlet excited state phthalimide moieties followed by desilylation of the intermediate -silylmethylthio cation radicals and cyclization by radical coupling is proposed. In contrast, photoreactions of N-(trimethylsilylmethylthioalkyl)Phthalimides in acetone follow different reaction routes to produce another cyclized products in which carbon-carbon bond formation takes place between the phthalimide carbonyl carbon and the carbon to silicon and sulfur atoms via triplet carbonyl hydrogen abstraction pathway. The normal singlet SET pathway dominates this triplet process for photoreactions of these substances in methanol while the triplet process dominates the singlet SET pathway for those in acetone. The efficient and regioselective cyclization reactions observed for photolyses in methanol represent synthetically useful processes for construction of medium and large ring heterocyclic compounds.
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single electron transfer induced photoaddition reactions of silyl enol ether to n methylphthalimide
Bulletin of The Korean Chemical Society, 2007Co-Authors: Jin Young Kim, Jung Hei Choi, Dae Won Cho, Ung Chan YoonAbstract:Photochemical reactions of N-methylphthalimide with silyl enol ethers have been explored. Irradiations of phthalimide (1) and cyclic silyl enol ethers (5a-b) are observed to promote formation of photoreduced Phthalimides and photoaddition products by sequential SET-desilylation pathways. The photoreaction of phthalimide (1) and acyclic silyl enol ethers (5c-d) leads to produce oxetanes which arise by competitive single electron transfer (SET) and classical 2+2 photocycloaddition (Parteno-Buchi reaction) pathways.
Huanfeng Jiang - One of the best experts on this subject based on the ideXlab platform.
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Carbonylation Access to Phthalimides Using Self-Sufficient Directing Group and Nucleophile
Journal of Organic Chemistry, 2017Co-Authors: Fanghua Ji, Jianxiao Li, Wanqing Wu, Xianwei Li, Huanfeng JiangAbstract:Herein we report a novel palladium-catalyzed oxidative carbonylation reaction for the synthesis of Phthalimides with high atom- and step-economy. In our strategy, the imine and H2O, which are generated in situ from the condensation of aldehyde and amine, serve as self-sufficient directing group and nucleophile, respectively. This method provides rapid access to Phthalimides starting from readily available materials in a one-pot manner. Various phthalimide derivatives are constructed efficiently, including medicinally and biologically active phthalimide-containing compounds.
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Carbonylation Access to Phthalimides Using Self-Sufficient Directing Group and Nucleophile
2017Co-Authors: Wei Guo, Huanfeng JiangAbstract:Herein we report a novel palladium-catalyzed oxidative carbonylation reaction for the synthesis of Phthalimides with high atom- and step-economy. In our strategy, the imine and H2O, which are generated in situ from the condensation of aldehyde and amine, serve as self-sufficient directing group and nucleophile, respectively. This method provides rapid access to Phthalimides starting from readily available materials in a one-pot manner. Various phthalimide derivatives are constructed efficiently, including medicinally and biologically active phthalimide-containing compounds
Fei Lian - One of the best experts on this subject based on the ideXlab platform.
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Electrochemical Dehydrogenative Imidation of N-Methyl-Substituted Benzylamines with Phthalimides for the Direct Synthesis of Phthalimide-Protected gem-Diamines
Organic Letters, 2018Co-Authors: Fei Lian, Kun Xu, Cheng-chu ZengAbstract:A general and green electrochemical dehydrogenative method for the imidation of N-methyl benzylamines with Phthalimides with excellent regioselectivities is reported for the first time. This operationally simple method offers a valuable tool to obtain structurally diverse phthalimide-protected gem-diamines.
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Electrochemical Dehydrogenative Imidation of N‑Methyl-Substituted Benzylamines with Phthalimides for the Direct Synthesis of Phthalimide-Protected gem-Diamines
2018Co-Authors: Fei Lian, Caocao Sun, Cheng-chu ZengAbstract:A general and green electrochemical dehydrogenative method for the imidation of N-methyl benzylamines with Phthalimides with excellent regioselectivities is reported for the first time. This operationally simple method offers a valuable tool to obtain structurally diverse phthalimide-protected gem-diamines
