| ŠEBEJ, Peter, Tomáš ŠOLOMEK, Ľubica HROUDNÁ, Pavla BRANCOVÁ and Petr KLÁN. Photochemistry of 2-Nitrobenzylidene Acetals. Journal of Organic Chemistry. Columbus, OH, USA: the American Chemical Society, 2009, vol. 74, No 22, p. 8647-8658. ISSN 0022-3263. |
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@article{852210,
author = {Šebej, Peter and Šolomek, Tomáš and Hroudná, Ľubica and Brancová, Pavla and Klán, Petr},
article_location = {Columbus, OH, USA},
article_number = {22},
keywords = {Photochemistry; Photoremovable protecting groups},
language = {eng},
issn = {0022-3263},
journal = {Journal of Organic Chemistry},
title = {Photochemistry of 2-Nitrobenzylidene Acetals},
volume = {74},
year = {2009}
}
TY - JOUR
ID - 852210
AU - Šebej, Peter - Šolomek, Tomáš - Hroudná, Ľubica - Brancová, Pavla - Klán, Petr
PY - 2009
TI - Photochemistry of 2-Nitrobenzylidene Acetals
JF - Journal of Organic Chemistry
VL - 74
IS - 22
SP - 8647-8658
EP - 8647-8658
PB - the American Chemical Society
SN - 00223263
KW - Photochemistry
KW - Photoremovable protecting groups
N2 - Photolysis of dihydroxy compounds (diols) protected as 2-nitrobenzylidene acetals (ONBA) and subsequent acid- or base-catalyzed hydrolysis of the 2-nitrosobenzoic acid ester intermediates result in an efficient and high-yielding release of the substrates. We investigated the scope and limitations of ONBA photochemistry and expanded upon earlier described two-step procedures to show that the protected diols of many structural varieties can also be liberated in a one-pot procedure. In view of the fact that the acetals of nonsymmetrically substituted diols are converted into one of the corresponding 2-nitrosobenzoic acid ester isomers with moderate to high regioselectivity, the mechanism of their formation was studied using various experimental techniques. The experimental data were found to be in agreement with DFT-based quantum chemical calculations that showed the preferential cleavage occurs on the acetal C-O bond in the vicinity of more electron-withdrawing (or less electron-donating) groups. The study also revealed considerable complexity in the cleavage mechanism and that the structural variations in the substrate can significantly alter the reaction pathway. This deprotection strategy was found to be also applicable for 2-thioethanol when released from the corresponding monothioacetal in the presence of a reducing agent, such as ascorbic acid.
ER -
ŠEBEJ, Peter, Tomáš ŠOLOMEK, Ľubica HROUDNÁ, Pavla BRANCOVÁ and Petr KLÁN. Photochemistry of 2-Nitrobenzylidene Acetals. \textit{Journal of Organic Chemistry}. Columbus, OH, USA: the American Chemical Society, 2009, vol.~74, No~22, p.~8647-8658. ISSN~0022-3263.
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