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Totalsynthese von natürlichem α‐Tocopherol. 1. Mitteilung. Herstellung bifunktioneller, optisch aktiver Synthesebausteine für die Seitenkette mit Hilfe mikrobiologischer Umwandlungen
Author(s) -
Leuenberger Hans Georg Wilhelm,
Boguth Walter,
Barner Richard,
Schmid Max,
Zell Reinhard
Publication year - 1979
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19790620210
Subject(s) - chemistry , enantioselective synthesis , stereochemistry , side chain , total synthesis , hydrolysis , double bond , bifunctional , natural product , organic chemistry , catalysis , polymer
Total Synthesis of Natural α‐Tocopherol. I. Preparation of Bifunctional Optically Active Precursors for the Synthesis of the Side Chain by Means of Microbiological Transformations Our concept for a new total synthesis of natural α‐tocopherol includes the synthesis of a corresponding (3 R , 7 R )‐configurated C 15 side chain to be built up by using twice an optically active C 5 unit together with an achiral C 5 end part. ( S )‐3‐methyl‐γ‐butyrolactone ( 11 ) and ( S )‐2‐methyl‐γ‐butyrolactone ( 9 ) represent suitable bifunctional C 5 ‐precursors for this purpose. These two key compounds have been prepared by fermentative transformation including the enantioselective hydrogenation of the double bond of ethyl‐4, 4‐dimethoxy‐3‐methylcrotonate ( 5 ) by bakers yeast (yielding 11 after ester hydrolysis and cyclization of the fermentation product) and ( E )‐3‐(1′, 3′‐dioxolan‐2′‐yl)‐2‐buten‐1‐ol ( 8 ) by the fungus Geotrichum candidum (yielding directly 9 ).