%0 Journal Article %T Functionalization of Oxazolo[4,5-b]pyrazines by Deprotometallation %+ Institut des Sciences Chimiques de Rennes (ISCR) %+ University of Copenhagen = Københavns Universitet (UCPH) %+ Université d'Oran 1 Ahmed Ben Bella [Oran] %+ Belarusian State University %A Bisballe, Niels %A Hedidi, Madani %A Demmer, Charles S. %A Chevallier, Floris %A Roisnel, Thierry %A Dorcet, Vincent %A Halauko, Yury S. %A Ivashkevich, Oleg A. %A Matulis, Vadim E. %A Bentabed-Ababsa, Ghenia %A Bunch, Lennart %A Mongin, Florence %Z Fonds Europeen de Developpement Regional (FEDER) funds %< avec comité de lecture %@ 1434-193X %J European Journal of Organic Chemistry %I Wiley-VCH Verlag %V 2018 %N 29 %P 3904-3913 %8 2018 %D 2018 %R 10.1002/ejoc.201800481 %K Oxazolopyrazines %K Deprotometallation %K Heterocycles %K Synthesis design %K Acidity %Z Chemical Sciences/Organic chemistryJournal articles %X Different 2-arylated oxazolo[4,5-b]pyrazines, obtained by palladium(II)-catalyzed domino reaction from 2,3-dichloropyrazine and the corresponding carboxamides, were functionalized by deprotometallation. Employing lithium 2,2,6,6-tetramethylpiperidine, in order to form a lithio derivative, and then trapping it by iodolysis, proved to be inefficient. However, the presence of a zinc-based in situ trap allowed most substrates to be functionalized. Deprotonation of the pyrazine ring was observed in the presence of tolyl and anisyl groups at the oxazole 2-position. In contrast, with chlorophenyl and thienyl groups in this 2-position, deprotonation rather occurred on these groups either competitively or exclusively. The regioselectivities were discussed in the light of calculated pK(a) values of the substrates in THF. Finally, in the case of 2-phenyloxazolo[4,5-b]pyrazine, we converted the mixture of 5- and 6-iodinated products into the corresponding 5,6-diiodide, which was further functionalized by a double Suzuki coupling. %G English %2 https://univ-rennes.hal.science/hal-01861420/document %2 https://univ-rennes.hal.science/hal-01861420/file/Mongin%20et%20al_Functionalization%20of%20oxazolo%5B4%2C5-b%5Dpyrazines%20by%20deprotometallation.pdf %L hal-01861420 %U https://univ-rennes.hal.science/hal-01861420 %~ UNIV-RENNES1 %~ CNRS %~ INSA-RENNES %~ ENSC-RENNES %~ ISCR %~ SCR-CD %~ SCR_CPM %~ STATS-UR1 %~ UR1-SPM %~ ISCR-PRATS %~ INC-CNRS %~ UR1-UFR-SPM %~ UR1-HAL %~ ISCR-CORINT %~ UR1-SDLM %~ TEST-UR-CSS %~ UNIV-RENNES %~ INSA-GROUPE %~ ISCR-CORINT1 %~ TEST-HALCNRS %~ UR1-MMS %~ ISCR-CORINT3 %~ TEST2-HALCNRS %~ TEST3-HALCNRS