Orthogonal Photocleavage of a Monochromophoric Linker

Kammari, Laxminarayana; Šolomek, Tomáš; Ngoy, Bokolombe P.; Heger, Dominik; Klán, Petr

doi:10.1021/ja1047736

Cited by 38 publications

(38 citation statements)

References 29 publications

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“…48 This linker thus combines the properties of two well-known photoremovable groups, 2-nitrobenzyl (section 3.1) and phenacyl moieties, in a single chromophore. Liberation of R′CO 2 H from the intermediate 2 requires the presence of an H-atom donor.…”

Section: Arylcarbonylmethyl Groupsmentioning

confidence: 99%

Photoremovable Protecting Groups in Chemistry and Biology: Reaction Mechanisms and Efficacy

et al. 2012

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Section: Arylcarbonylmethyl Groupsmentioning

confidence: 99%

Photoremovable Protecting Groups in Chemistry and Biology: Reaction Mechanisms and Efficacy

et al. 2012

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“…[3] Excited-state hydrogen transfer (ESHT), a process that stood at the origin of modern photochemistry, [2a] plays an essential role in the functionality of many chemical and biological systems. In particular, the phototautomerization of o-nitrobenzyl (oNB) derivatives 1 [4] results in a cascade of irreversible reactions that lead to the ejection of leaving groups (LGs) X (Scheme 1), a reaction that has found numerous applications in photoactivatable ("caged") compounds in chemistry, [5] biochemistry, [6] macromolecular [7] and neural sciences, [8] photolithography, [9] or the fabrication of DNA chips. [10] It has been shown that photoexcitation of 1 is followed by rapid (ca.…”

Section: Introductionmentioning

confidence: 99%

The Primary Steps in Excited‐State Hydrogen Transfer: The Phototautomerization of o‐Nitrobenzyl Derivatives

Šolomek

Bochet

Bally

2014

Chemistry A European J

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The quantum yield for the release of leaving groups from o-nitrobenzyl "caged" compounds varies greatly with the nature of these leaving groups, for reasons that have never been well understood. We found that the barriers for the primary hydrogen-atom transfer step and the efficient nonradiative processes on the excited singlet and triplet surfaces determine the quantum yields. The excited-state barriers decrease when the exothermicity of the photoreaction increases, in accord with Bell-Evans-Polanyi principle, a tool that has never been applied to a nonadiabatic photoreaction. We further introduce a simple ground-state predictor, the radical-stabilization energy, which correlates with the computed excited-state barriers and reaction energies, and that might be used to design new and more efficient photochemical processes.

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“…Apparently it is not the nucleofugacity, since quantum yields for the decay of the 4-acetyl-2-nitrobenzyl protected benzylalcohol in methanol was found to be 0.88 while it was only 0.051 for the corresponding phenylacetic acid. 29 In this paper we propose a simple predictive model to explain a series of quantum yields for the release of seven different commonly used leaving groups from o-nitroveratryl PPGs. Based on a minimal mechanistic scheme, these values are correlated with a measure that can be evaluated easily using standard quantum chemical calculations.…”

Section: Introductionmentioning

confidence: 99%

Photolysis of ortho-nitrobenzylic derivatives: the importance of the leaving group

Šolomek

Mercier

Bally

et al. 2012

Photochem Photobiol Sci

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Quantum yields for the photoinduced release of seven different commonly used leaving groups (LGs) from the o-nitroveratryl protecting group were measured. It was found that these quantum yields depend strongly on the nature of the LGs. We show that the quantum efficiency with which the LGs are released correlates with the stabilization that these LGs provide to o-nitrobenzyl-type radicals because radical stabilizing groups weaken the C-H bond that is cleaved in the photoinduced hydrogen atom transfer step, and hence lower the barrier for this process. At the same time these substituents lower the endothermicity of the thermal hydrogen atom transfer and thus increase the barrier for the reverse process, thereby enhancing the part of the initially formed aci-nitro intermediates which undergo cyclization (which ultimately leads to LG release). Radical stabilization energies computed by DFT methods are thus a useful predictor of the relative efficiency with which LGs are photoreleased from o-nitrobenzyl protecting groups.

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Orthogonal Photocleavage of a Monochromophoric Linker

Abstract: The 4-acetyl-2-nitrobenzyl moiety, substituted in both benzylic and phenacyl positions with leaving groups, has been proposed as a monochromophoric photocleavable linker. The attached groups can be disconnected selectively and orthogonally upon irradiation.

Cited by 38 publications

References 29 publications

Photoremovable Protecting Groups in Chemistry and Biology: Reaction Mechanisms and Efficacy

Photoremovable Protecting Groups in Chemistry and Biology: Reaction Mechanisms and Efficacy

The Primary Steps in Excited‐State Hydrogen Transfer: The Phototautomerization of o‐Nitrobenzyl Derivatives

Photolysis of ortho-nitrobenzylic derivatives: the importance of the leaving group

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