- Fast-Synthesis of α-Phosphonyloxy Ketones as Drug Scaffolds in a Capillary Microreactor
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A simple, room temperature approach for the fast single-step synthesis of α-phosphonyloxy ketone, a drug scaffold, has been developed which involves highly reactive species i.e., 1,2-dicarbonyls that readily react with trialkyl phosphites and formic acids in batch as well as in continuous-flow with the flow rate of 3 ml/min (tR = ~4 s). The present approach reduced the synthesis time from hours to minutes in batch, which was further lowered to a few seconds precisely controlled by single capillary microfluidics. A wide range of 1,2-dicarbonyl derivatives were smoothly transformed to their corresponding α-phosphonyloxy ketones in moderate to good yields (50–82 %) under optimized flow-reaction conditions. Further, the α-phosphonyloxy ketones produced can be utilized in batch process to form benzoin, oxazole core, and α,α′-diarylated carbonyl compounds in 82 %, 50 %, and 54 % yields, respectively, which are alternative key precursors/scaffolds of natural products and active pharmaceutical ingredients (APIs).
- Ramanjaneyulu, Bandaru T.,Vidyacharan, Shinde,Yim, Se Jun,Kim, Dong-Pyo
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supporting information
p. 7730 - 7734
(2019/12/24)
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- Lewis acid-promoted friedel-crafts alkylation reactions with α-ketophosphate electrophiles
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The BF3·OEt2-promoted nucleophilic substitution of α-aryl-α-ketophosphates to afford α,α-diaryl ketone products is described. Electron-rich α-ketophosphates perform best, with electron-neutral and electron-poor substrates also tolerated. The reaction is tolerant of a range of aromatic, heteroaromatic, and nonaromatic nucleophiles, with yields ranging from 44% to 84%. Enantioenriched starting material yields racemic product, suggesting an SN1 pathway via an acylcarbenium ion.
- Smith, Austin G.,Johnson, Jeffrey S.
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supporting information; experimental part
p. 1784 - 1787
(2010/09/05)
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