- Pyrrolidines and Piperidines by Ligand-Enabled Aza-Heck Cyclizations and Cascades of N-(Pentafluorobenzoyloxy)carbamates
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Ligand-enabled aza-Heck cyclizations and cascades of N-(pentafluorobenzoyloxy)carbamates are described. These studies encompass the first examples of efficient non-biased 6-exo aza-Heck cyclizations. The methodology provides direct and flexible access to carbamate protected pyrrolidines and piperidines.
- Hazelden, Ian R.,Carmona, Rafaela C.,Langer, Thomas,Pringle, Paul G.,Bower, John F.
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supporting information
p. 5124 - 5128
(2018/03/26)
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- Stereospecific Alkene Aziridination Using a Bifunctional Amino-Reagent: An Aza-Prilezhaev Reaction
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In situ deprotection (TFA) of O-Ts activated N-Boc hydroxylamines triggers intramolecular aziridination of N-tethered alkenes to provide complex N-heterocyclic ring systems. Synthetic and computational studies corroborate a diastereospecific aza-Prilezhaev-type mechanism. The feasibility of related intermolecular alkene aziridinations is also demonstrated.
- Farndon, Joshua J.,Young, Tom A.,Bower, John F.
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supporting information
p. 17846 - 17850
(2019/01/04)
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- Diverse N-Heterocyclic Ring Systems via Aza-Heck Cyclizations of N-(Pentafluorobenzoyloxy)sulfonamides
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Aza-Heck cyclizations initiated by oxidative addition of Pd0-catalysts into the N?O bond of N-(pentafluoro-benzoyloxy)sulfonamides are described. These studies, which encompass only the second class of aza-Heck reaction developed to date, provide direct access to diverse N-heterocyclic ring systems.
- Hazelden, Ian R.,Ma, Xiaofeng,Langer, Thomas,Bower, John F.
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supporting information
p. 11198 - 11202
(2016/10/13)
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- Asymmetric iodocyclization catalyzed by salen-CrIIICl: Its synthetic application to swainsonine
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The previously developed enantioselective iodocyclization of γ-hydroxy-cis-alkenes required 30 mol% of (R,R)-salen-CoII complex as chiral catalyst and 0.75 equivalent of N-chlorosuccinimide (NCS) as activator to produce 2-substituted tetrahydrofurans with 61 to 90% ee. Due to the considerable loading amount of the CoII complex, another more effective catalyst was pursued by screening (R,R)-salentransition metal complexes. When 10 mol % of the catalysts were applied with 0.5 equivalent of NCS, a higher level of stereoselectivity was attained with the corresponding CrIIICl (84% ee), MnIICl (52% ee) and CoII complexes (66% ee). Refinement of the conditions established a novel catalytic enantioselective iodocyclization protocol using iodine in the presence of 7 mol% of (R,R)-salen-CrIIICl complex activated by 0.7 equivalent of NCS in toluene to induce 74 to 93 % ee.
- Kwon, Hyo Young,Park, Chul Min,Lee, Sung Bae,Youn, Joo-Hack,Kang, Sung Ho
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p. 1023 - 1028
(2008/09/21)
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