- Photoinduced Palladium-Catalyzed Carbofunctionalization of Conjugated Dienes Proceeding via Radical-Polar Crossover Scenario: 1,2-Aminoalkylation and beyond
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A photoinduced palladium-catalyzed 1,2-carbofunctionalization of conjugated dienes has been developed. This mild modular approach, which does not require employment of exogeneous photosensitizers and external oxidants, allows for efficient and highly regio- and stereoselective synthesis of a broad range of allylic amines from readily available 1,3-dienes, alkyl iodides, and amines. Employment of O- and C-nucleophiles toward oxyalkylation and dialkylation products was also demonstrated. A putative π-allyl palladium radical-polar crossover path is proposed as a key event in this three-component coupling process. The utility of this protocol is highlighted by its application for derivatization of several amine-containing drugs.
- Gevorgyan, Vladimir,Kurandina, Daria,Shing Cheung, Kelvin Pak,Yata, Tetsuji
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supporting information
p. 9932 - 9937
(2020/06/27)
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- 1,2-Amino Alcohols via Cr/Photoredox Dual-Catalyzed Addition of α-Amino Carbanion Equivalents to Carbonyls
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Herein, we report the synthesis of protected 1,2-amino alcohols starting from carbonyl compounds and α-silyl amines. The reaction is enabled by a Cr/photoredox dual catalytic system that allows the in situ generation of α-amino carbanion equivalents which act as nucleophiles. The unique nature of this reaction was demonstrated through the aminoalkylation of ketones and an acyl silane, classes of electrophiles that were previously unreactive toward addition of alkyl-Cr reagents. Overall, this reaction broadens the scope of Cr-mediated carbonyl alkylations and discloses an underexplored retrosynthetic strategy for the synthesis of 1,2-amino alcohols.
- Schwarz, J. Luca,Kleinmans, Roman,Paulisch, Tiffany O.,Glorius, Frank
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supporting information
p. 2168 - 2174
(2020/03/03)
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- Catalyst free, visible-light promoted photoaddition reactions between C60 and N-trimethylsilylmethyl-substituted tertiary amines for synthesis of aminomethyl-1,2-dihydrofullerenes
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An efficient and benign method for the preparation of aminomethyl-substituted fullerenes has been developed. The process, involving catalyst free, visible-light irradiation of 10% EtOH-toluene solutions containing fullerene C60 and N-trimethyls
- Lim, Suk Hyun,Cho, Dae Won,Mariano, Patrick S.
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p. 383 - 391
(2017/12/28)
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- Electronic and steric effects controlling efficiencies of photoaddition reactions of fullerene C60with N-α-trimethylsilyl-N-alkyl-N-benzylamines
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Single electron transfer (SET)-promoted photoaddition reactions between fullerene C60and both various alkyl (Me, Et, i-Pr, t-Bu)- and para-substituted (p-Me, p-OMe, p-F, p-CF3) arene ring containing, N-α-trimethylsilyl-N-alkyl-N-benzylamines were explored to gain information about photoproduct profiles and how the electronic and steric nature of the amine substrates influence reaction efficiencies. The results show that visible light (λ?>?540?nm) irradiation of 10% EtOH-toluene solutions containing C60and N-α-trimethylsilyl-N-alkyl-N-benzylamines produce 1-aminomethyl-1,2-dihydrofullerenes as a sole photoproduct. In addition, SET-promoted photoaddition reactions of unsubstituted and para-electron donating group substituted arene ring containing N-α-trimethylsilyl-N-alkyl-N-benzylamines take place to give photoproducts more efficiently than those containing para-electron withdrawing group substituted arene rings. Moreover, although steric factors are less significant than the electronic nature of the amine substrates in governing reaction efficiencies, sterics do play a significant role in photoreactions of electron deficient amine substrates.
- Jeong, Ho Cheol,Lim, Suk Hyun,Sohn, Youngku,Kim, Young-Il,Jang, Hoeun,Cho, Dae Won,Mariano, Patrick S.
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supporting information
p. 949 - 954
(2017/02/19)
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- Method for the synthesis of amine-functionalized fullerenes involving set-promoted photoaddition reactions of -silylamines
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A novel method for the preparation of structurally diverse fullerene derivatives, which relies on the use of single electron transfer (SET)-promoted photochemical reactions between fullerene C60 and α-trimethylsilylamines, has been developed. Photoirradiation of 10% EtOH-toluene solutions containing C60 and α-silylamines leads to high-yielding, regioselective formation of 1,2-adducts that arise through a pathway in which sequential SET-desilylation occurs to generate α-amino and C60 anion radical pair intermediates, which undergo C-C bond formation. Protonation of generated α-aminofullerene anions gives rise to formation of monoaddition products that possess functionalized α-aminomethyl-substituted 1,2-dihydrofullerene structures. Observations made in this effort show that the use of EtOH in the solvent mixture is critical for efficient photoproduct formation. In contrast to typical thermal and photochemical strategies devised previously for the preparation of fullerene derivatives, the new photochemical approach takes place under mild conditions and does not require the use of excess amounts of substrates. Thus, the method developed in this study could broaden the scope of fullerene chemistry by providing a simple photochemical strategy for large-scale preparation of highly substituted fullerene derivatives. Finally, the α-aminomethyl-substituted 1,2-dihydrofullerene photoadducts are observed to undergo photoinduced fragmentation reactions to produce C60 and the corresponding N-methylamines.
- Lim, Suk Hyun,Yi, Jinju,Moon, Gyeong Min,Ra, Choon Sup,Nahm, Keepyung,Cho, Dae Won,Kim, Kyungmok,Hyung, Tae Gyung,Yoon, Ung Chan,Lee, Ga Ye,Kim, Soojin,Kim, Jinheung,Mariano, Patrick S.
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p. 6946 - 6958
(2014/08/18)
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- Heteroatom-facilitated lithiations of N-methyl-N-(trimethylsilyl)methyl-benzylamine and benzyl (trimethylsilyl)methyl ether with butyllithium
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Lithiation of the Si-methyl groups of N-methyl-N-[(trimethylsilyl)methyl]benzylamine (1) occurred in preference to ortho-lithiation of the benzyl group with butyllithium in ether. In a similar reaction with benzyl (trimethylsilyl)methyl ether (7), lithiat
- Mitsui,Marumo,Inoue-Ando,Kato,Sato
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p. 2195 - 2196
(2007/10/02)
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- Amine-Flavin Electron Transfer Photochemistry. Potential Models for Monoamine Oxidase Catalysis and Inhibition
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The photoreactions of 3-methyllumiflavin (3MLF) and a variety of amines have been explored.These studies have demonstrated that 3MLF undergoes efficient photoreactions with α-silyl tertiary benzylamines to generate 4a-adducts by pathways involving sequential SET and desilylation followed by radical coupling.These adducts are unstable substances that react rapidly with nucleophiles (e.g., MeOH, H2O, and NaBH4) and oxygen.Theyare also photolabile, providing the corresponding 4a-benzyldihydroflavin upon irradiation.Non-silicon-containing primary and secondary amines also participate in SET-promoted photoreactions with 3MLF.The amine cation radicals formed in these processes undergo further transformations to produce radical intermediates by either α-CH or NH deprotonation pathways.The potential relevance of these findings to the area of monoamine oxidase chemistry is considered.
- Kim, Jong-Man,Cho, In-Seop,Mariano, Patrick S.
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p. 4943 - 4955
(2007/10/02)
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- Ylide Reactions of Benzyldimethylammonium Halides
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Deprotonation of benzyldimethylammonium halides (10) with sodium amide or n-butyllithium afforded silylated ylide intermediates 11, which were rearranged into N,N-dimethyl-2-benzylamines (13) accompanied by the formation of Sommelet-Hauser and Stevens rearrangement products (12 and 22).The ylide formation by the cleavage of carbon-silicon bonds also is discussed in the reaction of 10 with sodium amide and lithium aluminum hydride.
- Sato, Yoshiro,Yagi, Yoko,Koto, Masami
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p. 613 - 617
(2007/10/02)
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