Chemoenzymatic synthesis of both enantiomers of α-tocotrienol

Chênevert, Robert; Courchesne, Gabriel; Pelchat, Nicholas

doi:10.1016/j.bmc.2006.03.035

Cited by 23 publications

(10 citation statements)

References 44 publications

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“…Subsequent deprotection of the tosyl group of 8 under mild conditions gave 9 in high chemical yield. The ester 9 is a common synthetic intermediate for D-a-tocopherol (27), D-a-tocotrienol (28), and (S)-trolox (29). Other tocopherols and their biologically active analogs could be easily prepared in a similar manner.…”

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confidence: 99%

High-turnover hypoiodite catalysis for asymmetric synthesis of tocopherols

Uyanik

Hayashi

Ishihara

2014

Science

175

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The diverse biological activities of tocopherols and their analogs have inspired considerable interest in the development of routes for their efficient asymmetric synthesis. Here, we report that chiral ammonium hypoiodite salts catalyze highly chemo- and enantioselective oxidative cyclization of γ-(2-hydroxyphenyl)ketones to 2-acyl chromans bearing a quaternary stereocenter, which serve as productive synthetic intermediates for tocopherols. Raman spectroscopic analysis of a solution of tetrabutylammonium iodide and tert-butyl hydroperoxide revealed the in situ generation of the hypoiodite salt as an unstable catalytic active species and triiodide salt as a stable inert species. A high-performance catalytic oxidation system (turnover number of ~200) has been achieved through reversible equilibration between hypoiodite and triiodide in the presence of potassium carbonate base. We anticipate that these findings will open further prospects for the development of high-turnover redox organocatalysis.

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confidence: 99%

High-turnover hypoiodite catalysis for asymmetric synthesis of tocopherols

Uyanik

Hayashi

Ishihara

2014

Science

175

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“…The 2H- chromene ( 2H- 1-benzopyran) moiety is a common structural feature of numerous biologically active molecules [1, 2] and is widely occurring in the structures of many natural flavonoids and anthocyanins [3], as well as the members of the vitamin E family (tocopherols and tocotrienes) [4–10]. A variety of methods are known for the synthesis of this class of compounds [2, 4–14], typically starting with 2-hydroxyacetophenone derivatives or directly from phenols via cyclization methods, electrophilic aromatic substitution, or by relying on palladium-catalyzed processes.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of 2H-chromenes and 1,2-dihydroquinolines from aryl aldehydes, amines, and alkenylboron compounds

Petasis

Butkevich

2009

Journal of Organometallic Chemistry

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The one-step reaction of salicylaldehydes with amines and alkenyl boronic acids or alkenyl trifluoroborates to form 2H-chromenes (2H-1-benzopyrans) has been investigated in more detail and new suitable conditions have been identified, including the use of tertiary amines and protic solvents including water. This process was applied to a concise synthesis of a tocopherol analog. The analogous condensation reaction between 2-sulfamidobenzaldehydes and alkenyl trifluoroborates provides an efficient synthesis of 1,2-dihydroquinoline derivatives.

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“…From a synthetic point of view, setting the chirality at position 2 is the major issue. This has been addressed so far in several ways, including kinetic resolution, , enzymatic resolution, − and asymmetric synthesis. − However, in spite of the high efficiency of both Trost's 14-19 and Tietze's methods 22,24 for synthesizing optically pure 2-methylchroman derivatives, the pioneering work of the Hoffman-La Roche group and a recent chemoenzymatic synthesis remain the only completed total asymmetric syntheses of any tocotrienols reported so far. ,− …”

Section: Introductionmentioning

confidence: 99%

A Short and Convenient Chemical Route to Optically Pure 2-Methyl Chromanmethanols. Total Asymmetric Synthesis of β-, γ-, and δ-Tocotrienols

et al. 2007

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With use of inexpensive commercially available raw materials, chromanmethanol precursors to the natural beta-, gamma-, and delta-tocotrienols have been prepared in high yield. Enzymatic resolution afforded chiral chromanmethanols in high enantiomeric excess. Subsequent attachment of the farnesyl side chain was high yielding, thus allowing the preparation of asymmetric beta-, gamma-, and delta-tocotrienols in one final step wherein simultaneous deprotection of the phenol and removal of the sulfone group occurs. This chemistry provides the first synthesis of natural-series beta-tocotrienol.

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Chemoenzymatic synthesis of both enantiomers of α-tocotrienol

Cited by 23 publications

References 44 publications

High-turnover hypoiodite catalysis for asymmetric synthesis of tocopherols

High-turnover hypoiodite catalysis for asymmetric synthesis of tocopherols

Synthesis of 2H-chromenes and 1,2-dihydroquinolines from aryl aldehydes, amines, and alkenylboron compounds

A Short and Convenient Chemical Route to Optically Pure 2-Methyl Chromanmethanols. Total Asymmetric Synthesis of β-, γ-, and δ-Tocotrienols

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