Enantioselective Acyloin Rearrangement of Acyclic Aldehydes Catalyzed by Chiral Oxazaborolidinium Ion

Cho, Soo Min; Lee, Si Yeon; Ryu, Do Hyun

doi:10.1021/acs.orglett.1c00314

Cited by 6 publications

(2 citation statements)

References 45 publications

(28 reference statements)

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“…The following was drafted from known procedures. − A solution of α-hydroxy acetal ( 44 , 45 , 46 , or 47 , 1.00 equiv, n mmol) in acetone ( V = 15 mL) was mixed with 10% aq. hydrochloric acid (1 mL) and equipped with a reflux condenser/hot plate apparatus.…”

Section: Experimental Sectionmentioning

confidence: 99%

Rapid, One-Step Synthesis of α-Ketoacetals via Electrophilic Etherification

et al. 2021

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Herein, we report a rapid, one-step synthesis of α-ketoacetals via electrophilic etherification of α-alkoxy enolates and monoperoxyacetals. Methyl, primary, and secondary α-ketoacetals were obtained in 44–63% yields from tetrahydropyranyl substrates; using methyl tetrahydropyranyl, alkyl tetrahydropyranyl, or methyl tetrahydrofuranyl peroxyacetals, however, methyl and primary products were isolated in 66–90% yields. The present method is applied to C–O bond formation at tertiary carbons, via alkyl and methyl peroxyacetals, with yields of 25–65%. Intermolecular “alkoxyl” transfer, from peroxyacetal to α-alkoxy enolate, relies heavily on decreased steric bulk surrounding the peroxide bond and site of etherification; additionally, we found the α-OCH3 group to be critical in ensuring product formation. α-Ketoacetals demonstrated excellent reactivity, as selective, nucleophilic attack at the unprotected carbonyl furnished α-hydroxy acetals in 80–100% yields; subsequent hydrolysis of the foregoing compounds provided α-hydroxy aldehydes in yields of 58–90%.

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Section: Experimental Sectionmentioning

confidence: 99%

Rapid, One-Step Synthesis of α-Ketoacetals via Electrophilic Etherification

et al. 2021

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“…Recently, our group reported the catalytic asymmetric Friedel–Crafts alkylation of furans with in situ generated o -quinone methides ( o -QMs) in the presence of chiral oxazaborolidinium ion (COBI) as a Lewis acid catalyst . Encouraged by these positive outcomes, we envisioned a similar reaction with glyoxals to form optically active α-hydroxyketones.…”

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confidence: 99%

Enantioselective Friedel–Crafts Reaction of Heteroaromatic Compounds with Glyoxals Catalyzed by Chiral Oxazaborolidinium Ion Catalyst

Han,

Seo,

Ryu

2023

Org. Lett.

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A catalytic enantioselective Friedel–Crafts reaction of various heteroaromatic compounds with glyoxals has been developed. In the presence of a chiral oxazaborolidinium ion catalyst, the reaction provided chiral α-hydroxyketones in high yield (up to 96%) with excellent enantioselectivity (up to >99% ee). The synthetic utility of this method was illustrated by conversion of the products to various derivatives such as 1,2-diol and β-amino alcohol.

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