- Photocatalytic Hydroaminoalkylation of Styrenes with Unprotected Primary Alkylamines
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Catalytic, intermolecular hydroaminoalkylation (HAA) of styrenes provides a powerful disconnection for pharmacologically relevant γ-arylamines, but current methods cannot utilize unprotected primary alkylamines as feedstocks. Metal-catalyzed HAA protocols are also highly sensitive to α-substitution on the amine partner, and no catalytic solutions exist for α-tertiary γ-arylamine synthesis via this approach. We report a solution to these problems using organophotoredox catalysis, enabling a direct, modular, and sustainable preparation of α-(di)substituted γ-arylamines, including challenging electron-neutral and moderately electron-rich aryl groups. A broad range of functionalities are tolerated, and the reactions can be run on multigram scale in continuous flow. The method is applied to a concise, protecting-group-free synthesis of the blockbuster drug Fingolimod, as well as a phosphonate mimic of itsin vivoactive form (by iterative α-C-H functionalization of ethanolamine). The reaction can also be sequenced with an intramolecularN-arylation to provide a general and modular access to valuable (spirocyclic) 1,2,3,4-tetrahydroquinolines and 1,2,3,4-tetrahydronaphthyridines. Mechanistic and kinetic studies support an irreversible hydrogen atom transfer activation of the alkylamine by the azidyl radical and some contribution from a radical chain. The reaction is photon-limited and exhibits a zero-order dependence on amine, azide, and photocatalyst, with a first-order dependence on styrene.
- Askey, Hannah E.,Grayson, James D.,Tibbetts, Joshua D.,Turner-Dore, Jacob C.,Holmes, Jake M.,Kociok-Kohn, Gabriele,Wrigley, Gail L.,Cresswell, Alexander J.
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supporting information
p. 15936 - 15945
(2021/10/12)
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- Synthesis, stability, and implications of phosphothioate agonists of sphingosine-1-phosphate receptors
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Phosphothioates may provide metabolic stability when compared to their phosphate counterparts, while retaining the potency and efficacy as agonists at sphingosine-1-phosphate (S1P) G-protein coupled receptors. Unlike their phosphate precursors, phosphothi
- Foss Jr., Frank W.,Clemens, Jeremy J.,Davis, Michael D.,Snyder, Ashley H.,Zigler, Molly A.,Lynch, Kevin R.,Macdonald, Timothy L.
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p. 4470 - 4474
(2007/10/03)
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