- Photo-induced radical borylation of hemiacetals via C–C bond cleavage
-
In this study, we reported a photo-induced radical borylation of hemiacetal derivatives via C–C bond cleavage. This transformation can be realized under mild conditions with simple reaction settings and irradiation of visible light. A series of substrates, including both cyclic and linear hemiacetal derivatives, were effectively transformed to the borylation product in moderate to good yields. Finally, the mechanism was studied in detail by DFT calculations, suggesting insight of the radical borylation process.
- Liu, Qianyi,Zhang, Jianning,Zhang, Lei,Mo, Fanyang
-
supporting information
(2021/01/05)
-
- INFANT FORMULA CONTAINING AN AROMA COMPOSITION FOR USE AS FRAGRANCE
-
The invention relates to a nutraceutical composition such as infant formula or infant food comprising a) a defined aroma composition; b) a methodology for developing, maintaining certain aroma constituents in the infant formula and an aroma or fragrance composition to be used to increase the acceptance of a person or an object by the baby or new born.
- -
-
-
- New strategies in carbonylation chemistry: The synthesis of δ-lactones from saturated alcohols and CO
-
This paper describes the δ-carbonylation of saturated alcohols which uses a 1,5-hydrogen-transfer reaction of alkoxyl radicals and subsequent carbonylation at the δ-carbon atoms as the key. The carbonylation reactions of five classes of saturated alcohols, namely, primary alcohols having primary δ-carbons, primary alcohols having secondary δ-carbons, primary alcohols having tertiary δ-carbons, secondary alcohols having primary δ- carbons, secondary alcohols having secondary δ-carbons, were carded out, in which lead tetraacetate (LTA) was used as a one-electron oxidant to generate the alkoxyl radicals. Carbonylation of these saturated alcohols, except for primary alcohols having tertiary δ-carbons, took place to afford δ-lactones in moderate to good yields. The mechanism of the remote carbonylation likely involves (1) alkoxyl radical generation via LTA oxidation of a saturated alcohol, (2) conversion of this alkoxyl radical to a δ-hydroxyalkyl radical by a 1,5-hydrogen-transfer reaction, (3) CO trapping of the δ-hydroxyalkyl radical yielding an acyl radical, and (4) oxidation and cyclization of the acyl radical to give a δ-lactone. A metal salt-free system was also tested for a substrate derived from a tertiary alcohol having a secondary δ- carbon; the photolysis of an alkyl 4-nitrobenzenesulfenate under CO pressures gave a δ-lactone in moderate yield.
- Tsunoi, Shinji,Ryu, Ilhyong,Okuda, Tohru,Tanaka, Minoru,Komatsu, Mitsuo,Sonoda, Noboru
-
p. 8692 - 8701
(2007/10/03)
-
- Catalytic oxidation of alkyl- and cycloalkylcyclanones into lactones
-
Pilot-plant syntheses of alkyl and cycloalkylcyclanones and their subsequent liquid-phase oxidation into lactones are described. Characteristics of resulting intermediates and target products are reported.
- Abbasov,Alimardanov,Suleimanova
-
p. 621 - 626
(2007/10/03)
-
- Biosynthesis of the Hypotensive Metabolite Oudenone by Oudemansiella radicata. 1. Intact Incorporation of a Tetraketide Chain Elongation Intermediate
-
The biosynthesis of the fungal metabolite oudenone (1) was investigated in cultures of Oudemansiella radicata.Feeding experiments using 13C- and 2H-labeled precursors, as well as NMR analyses of the labeled metabolite, suggested a polyketide origin.The incorporation of six acetate units into the carbon skeleton of 1 was observed when cultures were fed the N-acetylcysteamine thioester derivative of 13C-labeled acetate.Labeling of oudenone (1) from succinate or L-glutamic acid was not observed, whereas the pattern of 13C labeling from succinate was identical to that observed with acetate.The proposed advanced intermediate (5S)-5-hydroxyoctanoic acid (2) was synthesized as the deuterium labeled N-acetylcysteamine thioester derivative (S)-19 and successfully incorporated into 1.A biosynthetic scheme and cyclization mechanism, consistent with the experimental data, is proposed.
- Tsantrizos, Youla S.,Zhou, Fei,Famili, Parsa,Yang, Xianshu
-
p. 6922 - 6929
(2007/10/03)
-
- Synthesis of γ- and δ-Lactones via Radical CC-Bond Formation Reaction
-
Lactones 5 and 6 can be synthesized via solvomercuration of alkenes 1 and reductive CC-bond formation with acrylonitrile.
- Giese, Bernd,Hasskerl, Thomas,Luening, Ulrich
-
p. 859 - 861
(2007/10/02)
-
- Direct Oxidation of Alkanoic Acids and their Amides to γ-Lactones by Peroxydisulphate-containing Systems
-
The reaction of one-electron oxidation of alkanoic acids (I) and their amides (VI) on treatment with Na2S2O8-containing systems has been studied.As a result of the direct one-pot reaction acids (I) and amides (VI) are converted into γ and δ-lactones, the reaction being regioselective and leading mainly to γ-lactones in up to 35percent yield.The regioselectivity of the oxidative lactonisation depends greatly on the nature of alkyl substituents.The results obtained are presented in terms of a mechanism suggesting the generation of acyloxyl and amidyl radicals from (I) and (VI), respectively, followed by a rearrangement via a 1,5- or 1,6-H shift into the corresponding 3- and 4-carboxy- or -carboxamido-alkyl ra The latter undergo oxidative cyclisation to produce γ and δ lactones.The system Na2S2O8-NaCl-NaOH converts carboxamides (VI) into amines with loss of one carbon atom as a result of a Hoffmann type rearrangement.
- Nikishin, Gennady I.,Svitanko, Igor V.,Troyansky, Emmanuil I.
-
p. 595 - 602
(2007/10/02)
-
