14218-11-2Relevant articles and documents
Nickel-Catalyzed Radical Migratory Coupling Enables C-2 Arylation of Carbohydrates
Zhao, Gaoyuan,Yao, Wang,Kevlishvili, Ilia,Mauro, Jaclyn N.,Liu, Peng,Ngai, Ming-Yu
, p. 8590 - 8596 (2021)
Nickel catalysis offers exciting opportunities to address unmet challenges in organic synthesis. Herein we report the first nickel-catalyzed radical migratory cross-coupling reaction for the direct preparation of 2-Aryl-2-deoxyglycosides from readily available 1-bromosugars and arylboronic acids. The reaction features a broad substrate scope and tolerates a wide range of functional groups and complex molecular architectures. Preliminary experimental and computational studies suggest a concerted 1,2-Acyloxy rearrangement via a cyclic five-membered-ring transition state followed by nickel-catalyzed carbon-carbon bond formation. The novel reactivity provides an efficient route to valuable C-2-Arylated carbohydrate mimics and building blocks, allows for new strategic bond disconnections, and expands the reactivity profile of nickel catalysis.
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Mazzeno
, p. 1039 (1950)
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A Substituent-Directed Strategy for the Selective Synthesis of L-Hexoses: An Expeditious Route to L-Idose
See, Nicholas W.,Wimmer, Norbert,Krenske, Elizabeth H.,Ferro, Vito
, p. 1575 - 1584 (2021/03/03)
L-Hexoses are rare but biologically significant components of various important biomolecules. However, most are prohibitively expensive (if commercially available) which limits their study and biotechnological exploitation. New, efficient methods to access L-hexoses and their derivatives are thus of great interest. In a previous study, we showcased a stereoselective Bu3SnH-mediated transformation of a 5-C-bromo-D-glucuronide to an L-iduronide. We have now drawn inspiration from this result to derive a new methodology – one that can be harnessed to access other L-hexoses. DFT calculations demonstrate that a combination of a β-F at the anomeric position and a methoxycarbonyl substituent at C-6 is key to optimising the selectivity for the L-hexose product. Our investigations have also culminated in the development of the shortest known synthetic route to a derivative of L-idose from a commercially available starting material (45 % yield over 3 steps). Collectively, these results address the profound lack of understanding of how to synthesise L-hexoses in a stereoselective fashion.
Excited-State Palladium-Catalyzed 1,2-Spin-Center Shift Enables Selective C-2 Reduction, Deuteration, and Iodination of Carbohydrates
Zhao, Gaoyuan,Yao, Wang,Mauro, Jaclyn N.,Ngai, Ming-Yu
supporting information, p. 1728 - 1734 (2021/02/06)
Excited-state catalysis, a process that involves one or more excited catalytic species, has emerged as a powerful tool in organic synthesis because it allows access to the excited-state reaction landscape for the discovery of novel chemical reactivity. Herein, we report the first excited-state palladium-catalyzed 1,2-spin-center shift reaction that enables site-selective functionalization of carbohydrates. The strategy features mild reaction conditions with high levels of regio- and stereoselectivity that tolerate a wide range of functional groups and complex molecular architectures. Mechanistic studies suggest a radical mechanism involving the formation of hybrid palladium species that undergoes a 1,2-spin-center shift followed by the reduction, deuteration, and iodination to afford functionalized 2-deoxy sugars. The new reactivity will provide a general approach for the rapid generation of natural and unnatural carbohydrates.
