The role of SET in the deprotection of (thio)ketals under photosensitization by π-acceptors

Fasani, Elisa; Freccero, Mauro; Mella, Mariella; Albini, Angelo

doi:10.1016/s0040-4020(96)01123-4

Cited by 25 publications

(9 citation statements)

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“…It has been reported that dithioacetals can form radical species under irradiation in similar conditions . Therefore, the time evolution of the reaction was monitored by HPLC in the presence of TEMPO.…”

Section: Figurementioning

confidence: 99%

Rewiring Chemical Networks Based on Dynamic Dithioacetal and Disulfide Bonds

Orrillo

La–Venia

Escalante

et al. 2018

Chemistry A European J

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The control of the connectivity between nodes of synthetic networks is still largely unexplored. To address this point we take advantage of a simple dynamic chemical system with two exchange levels that are mutually connected and can be activated simultaneously or sequentially. Dithioacetals and disulfides can be exchanged simultaneously under UV light in the presence of a sensitizer. Crossover reactions between both exchange processes produce a fully connected chemical network. On the other hand, the use of acid, base or UV light connects different nodes allowing network rewiring.

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Section: Figurementioning

confidence: 99%

Rewiring Chemical Networks Based on Dynamic Dithioacetal and Disulfide Bonds

Orrillo

La–Venia

Escalante

et al. 2018

Chemistry A European J

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“…Further oxidation of the latter and reaction with CH 3 OH yield dimethyl ketals 8 and 9 29. Photoinduced deprotection of ketals by CA30 and a water work‐up affords the observed ketones 5 and 6 . In the absence of CH 3 OH or another oxygen‐centered nucleophilic species such as the residual water present in the CH 3 CN solvent, CA ·– or NO 3 – should also be responsible for the formation of the ketones 31.…”

Section: Mechanistic Discussionmentioning

confidence: 93%

Photochemical Electron‐Transfer Generation of Arylthiirane Radical Cations with Tetranitromethane and Chloranil — Some Novel Observations

2006

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The radical cations from 2,2,3,3‐tetraphenylthiirane (1a), 2,2‐bis(4‐methoxyphenyl)‐3,3‐diphenylthiirane (1b), and trans‐2,3‐diphenylthiirane (1c) have been generated by photoinduced electron transfer (PET) reactions with tetranitromethane [C(NO2)4] and chloranil (CA). A charge‐transfer complexe (CTC) absorption is observed by UV/Vis spectroscopy between thiiranes (1) and C(NO2)4. On the other hand, quenching studies with azulene suggest that the ET reaction occurs between thiiranes and the triplet CA (3CA). The photochemical reaction of the CTC between thiiranes 1 and C(NO2)4 yields mainly the corresponding alkenes from the fragmentation of the radical‐cation intermediate 1·+, together with the products derived from nitration on the phenyl rings. However, oxygen transfer to afford the sulfoxides is not found. A marked solvent effect is observed in this reaction, with cage coupling favored in CH2Cl2 (nitration derivatives as primary products) and non‐cage coupling observed in CH3CN (the alkene as the primary product). The PET reactions between 1a–b and CA, in the presence of CH3OH (or another possible oxygen‐centered nucleophile), give the ketone derivatives through ring opening, followed by oxidative cleavage. Conversely, under the same experimental conditions, the thiirane 1c affords only trans‐stilbene 2c. This different behavior is ascribed to a different spin density in the corresponding singly occupied molecular orbital (SOMO) of the radical cation. For 1c+·, the spin density is concentrated at the sulfur atom, whereas for 1a·+ and 1b·+, the charge is distributed onto the aromatic rings. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

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“…It is noteworthy that photosensitized oxygenation of these derivatives resulting in cleavage to carbonyl compounds is documented. 28,29 However, microwave-assisted solid-state oxygen-mediated dethioacetalization has not yet been reported to the best of our knowledge.…”

Section: Methodsmentioning

confidence: 99%