Synthetic utility of iodic acid in the oxidation of benzylic alcohols to aromatic aldehydes and ketones

Imai, Sho; Togo, Hideo

doi:10.1016/j.tet.2016.09.019

Cited by 15 publications

(4 citation statements)

References 36 publications

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“…colorless oil liquid; 35 mg, 79% yield; 1H NMR (600 MHz, CDCl 3 ) δ 10.56 (s, 1H), 6.90 (s, 2H), 2.58 (s, 6H), 2.32 (s, 3H); 13 C{ 1 H} NMR (150 MHz, CDCl 3 ) δ 193.0, 143.8, 141.5, 130.5, 129.9, 21.4, 20.5. The physical and spectral data were consistent with those previously reported …”

Section: Methodssupporting

confidence: 91%

Chemoselective Reduction of Sterically Demanding N,N-Diisopropylamides to Aldehydes

et al. 2017

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A sequential one-pot process for chemoselectively reducing sterically demanding N,N-diisopropylamides to aldehydes has been developed. In this reaction, amides are activated with EtOTf to form imidates, which are reduced with LiAlH(OR) [R = t-Bu, Et] to give aldehydes by hydrolysis of the resulting hemiaminals. The non-nucleophilic base 2,6-DTBMP remarkably improves reaction efficiency. The combination of EtOTf/2,6-DTBMP and LiAlH(O-t-Bu) was found to be optimal for reducing alkyl, alkenyl, alkynyl, and 2-monosubstituted aryl N,N-diisopropylamides. In contrast, EtOTf and LiAlH(OEt) in the absence of base were found to be optimal for reducing extremely sterically demanding 2,6-disubstituted N,N-diisopropylbenzamides. The reaction tolerates various reducible functional groups, including aldehyde and ketone. H NMR studies confirmed the formation of imidates stable in water. The synthetic usefulness of this methodology was demonstrated with N,N-diisopropylamide-directed ortho-metalation and C-H bond activation.

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Section: Methodssupporting

confidence: 91%

Chemoselective Reduction of Sterically Demanding N,N-Diisopropylamides to Aldehydes

et al. 2017

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“…Benzophenone (3g): 17 oil, 38 mg, quantitative yield; 1 H NMR (400 MHz, CDCl 3 ) δ 7.81 (d, J = 7.2 Hz, 4H), 7.59 (t, J = 7.4 Hz, 2H), 7.49 (t, J = 7.6 Hz, 4H); 13 C{ 1 H} NMR (100 MHz, CDCl 3 ) δ 196. 7, 137.5, 132.4, 130.0, 128.2.…”

Section: ■ Conclusionmentioning

confidence: 99%

Redetermination of the Structure of a Water-Soluble Hypervalent Iodine(V) Reagent AIBX and Its Synthetic Utility in the Oxidation of Alcohols and Synthesis of Isoxazoline N-Oxides

et al. 2019

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The structure of a water-soluble hypervalent iodine(V) reagent AIBX is re-examined through its singlecrystal X-ray analysis and theoretical calculations including Mayer bond order and localized orbital locator (LOL) and AIBX is believed to be a pseudocyclic iodylarene because of the strong electron-withdrawing nature of the trimethylammonium cation on its phenyl ring, which would decrease the electron density of carboxylic anion and make the orthocarboxyl oxygen anion incapable to form hypervalent bond with iodine atom. However, the cyclic benziodoxole structure of AIBX could be obtained by adding a Brønsted acid, which was supported by the calculation result including the increase of Mayer bond order and the shortening of the I−O bond length. Moreover, the fact that the system of AIBX and TFA could oxidize various alcohols to their corresponding carbonyl compounds would indicate that AIBX constitutes a cyclic benziodoxole structure under acidic conditions. In addition, an efficient method has been developed for the synthesis of isoxazoline N-oxides via AIBX-induced dehydrogenative cyclization using β-keto esters as substrates and methyl nitroacetate as a nucleophile.

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Section: Experimental Sectionmentioning

confidence: 99%

“…Following Typical Procedure II, the reaction of Fe(NO 3 ) 3 ·9H 2 O (20.4 mg, 0.05 mmol), 4-OH-TEMPO (8.7 mg, 0.05 mmol), NaCl (2.9 mg, 0.05 mmol), and 1i (169.2 mg, 98% purity, 1.0 mmol) in DCE (4.0 mL) for 6 h afforded 2i (156.2 mg, 95%) as a solid (eluent: petroleum ether/ethyl acetate = 20/1). Mp 61.7–62.9 °C (ethyl acetate/petroleum ether; lit . 61–63 °C); 1 H NMR (400 MHz, CDCl 3 ) δ 10.11 (s, 1H, CHO), 8.20 (d, J = 8.0 Hz, 2H, Ar–H), 7.96 (d, J = 8.4 Hz, 2H, Ar–H), 3.97 (s, 3H, CH 3 ); 13 C NMR (100 MHz, CDCl 3 ) δ 191.6, 165.9, 139.0, 135.0, 130.1, 129.4, 52.5; IR (neat, cm –1 ) 2962, 2887, 1722, 1682, 1575, 1502, 1434, 1391, 1280, 1199, 1106, 1012; MS (EI, 70 eV) m / z (%) 164 (M + , 59.96), 133 (100).…”

Section: Experimental Sectionmentioning

confidence: 99%

Iron-Catalyzed Aerobic Oxidation of Alcohols: Lower Cost and Improved Selectivity

Jiang

Liu

2019

Org. Process Res. Dev.

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An aerobic oxidation reaction of alcohols toward aldehydes or ketones using catalytic amounts of Fe(NO3)3·9H2O, 4-OH-TEMPO, and NaCl has been developed. Compared with the former catalytic system with TEMPO developed in this group, the new protocol using 4-OH-TEMPO, which is much cheaper on an industrial scale, accomplished the transformation with a higher selectivity, especially for aliphatic alcohols toward aldehydes. α,β-Unsaturated alkynals or alkynones can be efficiently synthesized from propargyl alcohols, which has been much less studied in the literature.

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Synthetic utility of iodic acid in the oxidation of benzylic alcohols to aromatic aldehydes and ketones

Cited by 15 publications

References 36 publications

Chemoselective Reduction of Sterically Demanding N,N-Diisopropylamides to Aldehydes

Chemoselective Reduction of Sterically Demanding N,N-Diisopropylamides to Aldehydes

Redetermination of the Structure of a Water-Soluble Hypervalent Iodine(V) Reagent AIBX and Its Synthetic Utility in the Oxidation of Alcohols and Synthesis of Isoxazoline N-Oxides

Iron-Catalyzed Aerobic Oxidation of Alcohols: Lower Cost and Improved Selectivity

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