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Thomas Lecourt - One of the best experts on this subject based on the ideXlab platform.
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straightforward entry toward highly substituted 2 3 dihydrobenz b oxepines by ring expansion of benzopyryliums with donor acceptor diazo compounds
Organic Letters, 2018Co-Authors: Thibaut Courant, Morgane Pasco, Thomas LecourtAbstract:Ylide-type reactivity of diazo compounds is exploited in a new way to prepare benzo[b]oxepines thanks to the formation of three chemical bonds and two contiguous and highly substituted stereocenters in a single pot. This Cationic Reaction cascade first involves addition of a donor–acceptor-substituted diazo compound to a benzopyrylium. Selective 1,2 migration of the endocyclic C–C bond then results in a ring-expansion and generates a second oxocarbenium that is trapped by a nucleophile added sequentially.
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Straightforward Entry toward Highly Substituted 2,3-Dihydrobenz[b]oxepines by Ring Expansion of Benzopyryliums with Donor–Acceptor Diazo Compounds
2018Co-Authors: Thibaut Courant, Morgane Pasco, Thomas LecourtAbstract:Ylide-type reactivity of diazo compounds is exploited in a new way to prepare benzo[b]oxepines thanks to the formation of three chemical bonds and two contiguous and highly substituted stereocenters in a single pot. This Cationic Reaction cascade first involves addition of a donor–acceptor-substituted diazo compound to a benzopyrylium. Selective 1,2 migration of the endocyclic C–C bond then results in a ring-expansion and generates a second oxocarbenium that is trapped by a nucleophile added sequentially
Thibaut Courant - One of the best experts on this subject based on the ideXlab platform.
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straightforward entry toward highly substituted 2 3 dihydrobenz b oxepines by ring expansion of benzopyryliums with donor acceptor diazo compounds
Organic Letters, 2018Co-Authors: Thibaut Courant, Morgane Pasco, Thomas LecourtAbstract:Ylide-type reactivity of diazo compounds is exploited in a new way to prepare benzo[b]oxepines thanks to the formation of three chemical bonds and two contiguous and highly substituted stereocenters in a single pot. This Cationic Reaction cascade first involves addition of a donor–acceptor-substituted diazo compound to a benzopyrylium. Selective 1,2 migration of the endocyclic C–C bond then results in a ring-expansion and generates a second oxocarbenium that is trapped by a nucleophile added sequentially.
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Straightforward Entry toward Highly Substituted 2,3-Dihydrobenz[b]oxepines by Ring Expansion of Benzopyryliums with Donor–Acceptor Diazo Compounds
2018Co-Authors: Thibaut Courant, Morgane Pasco, Thomas LecourtAbstract:Ylide-type reactivity of diazo compounds is exploited in a new way to prepare benzo[b]oxepines thanks to the formation of three chemical bonds and two contiguous and highly substituted stereocenters in a single pot. This Cationic Reaction cascade first involves addition of a donor–acceptor-substituted diazo compound to a benzopyrylium. Selective 1,2 migration of the endocyclic C–C bond then results in a ring-expansion and generates a second oxocarbenium that is trapped by a nucleophile added sequentially
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photoredox initiated α alkylation of imines through a three component radical Cationic Reaction
ChemInform, 2012Co-Authors: Thibaut Courant, Geraldine MassonAbstract:Key features of the approach are the wide substance scope, short Reaction times, high atom-economy (no side products) and good to excellent chemical yields.
Morgane Pasco - One of the best experts on this subject based on the ideXlab platform.
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straightforward entry toward highly substituted 2 3 dihydrobenz b oxepines by ring expansion of benzopyryliums with donor acceptor diazo compounds
Organic Letters, 2018Co-Authors: Thibaut Courant, Morgane Pasco, Thomas LecourtAbstract:Ylide-type reactivity of diazo compounds is exploited in a new way to prepare benzo[b]oxepines thanks to the formation of three chemical bonds and two contiguous and highly substituted stereocenters in a single pot. This Cationic Reaction cascade first involves addition of a donor–acceptor-substituted diazo compound to a benzopyrylium. Selective 1,2 migration of the endocyclic C–C bond then results in a ring-expansion and generates a second oxocarbenium that is trapped by a nucleophile added sequentially.
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Straightforward Entry toward Highly Substituted 2,3-Dihydrobenz[b]oxepines by Ring Expansion of Benzopyryliums with Donor–Acceptor Diazo Compounds
2018Co-Authors: Thibaut Courant, Morgane Pasco, Thomas LecourtAbstract:Ylide-type reactivity of diazo compounds is exploited in a new way to prepare benzo[b]oxepines thanks to the formation of three chemical bonds and two contiguous and highly substituted stereocenters in a single pot. This Cationic Reaction cascade first involves addition of a donor–acceptor-substituted diazo compound to a benzopyrylium. Selective 1,2 migration of the endocyclic C–C bond then results in a ring-expansion and generates a second oxocarbenium that is trapped by a nucleophile added sequentially
Katrin Dulitz - One of the best experts on this subject based on the ideXlab platform.
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penning collisions between supersonically expanded metastable he atoms and laser cooled li atoms
Journal of Chemical Physics, 2019Co-Authors: Jonas Grzesiak, Takamasa Momose, F Stienkemeier, M Mudrich, Katrin DulitzAbstract:We describe an experimental setup comprised of a discharge source for supersonic beams of metastable He atoms and a magneto-optical trap (MOT) for ultracold Li atoms that makes it possible to study Penning ionization and associative ionization processes at high ion count rates. The Cationic Reaction products are analyzed using a novel ion detection scheme which allows for mass selection, a high ion extraction efficiency, and a good collision-energy resolution. The influence of elastic He–Li collisions on the steady-state Li atom number in the MOT is described, and the collision data are used to estimate the excitation efficiency of the discharge source. We also show that Penning collisions can be directly used to probe the temperature of the Li cloud without the need for an additional time-resolved absorption or fluorescence detection system.We describe an experimental setup comprised of a discharge source for supersonic beams of metastable He atoms and a magneto-optical trap (MOT) for ultracold Li atoms that makes it possible to study Penning ionization and associative ionization processes at high ion count rates. The Cationic Reaction products are analyzed using a novel ion detection scheme which allows for mass selection, a high ion extraction efficiency, and a good collision-energy resolution. The influence of elastic He–Li collisions on the steady-state Li atom number in the MOT is described, and the collision data are used to estimate the excitation efficiency of the discharge source. We also show that Penning collisions can be directly used to probe the temperature of the Li cloud without the need for an additional time-resolved absorption or fluorescence detection system.
K N Houk - One of the best experts on this subject based on the ideXlab platform.
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chemical hermaphroditism the potential of the cr co 3 moiety to stabilize transition states and intermediates with anionic Cationic or radical character at the benzylic position
Journal of the American Chemical Society, 1999Co-Authors: Craig A Merlic, Joseph C Walsh, And Dean J Tantillo, K N HoukAbstract:It is known that both benzylic cations and anions are stabilized by Cr(CO)3 complexation. This unusual characteristic of chromium arenes has been the subject of many synthetic, spectroscopic, and physical organic studies over the last four decades. The effect of Cr(CO)3 on benzylic radicals has received comparatively little attention, however. In this report, cyclopropylcarbinyl anions, cations, and radicals substituted with both phenyl and Cr(CO)3-phenyl groups are shown to rearrange via ring-opening to produce, selectively, Cr(CO)3-stabilized benzylic anions, cations, and radicals, implying that the Cr(CO)3 moiety is capable of stabilizing transition states with ionic or radical character at the benzylic position. The highest selectivity (>99:<1) was observed in the anionic Reaction, slightly lesser selectivity (95:5) was observed in the Cationic Reaction, and only modest selectivity (2.5:1) was observed in the radical Reaction. A parallel trend in ground-state stabilities of Cr(CO)3-complexed benzyl an...