Stereocontrolled Synthesis of a Cn-Cn+6Building Block for the Unnatural Enantiomers of Important Polyol,Polyene Antibiotics from an Epoxy Alcohol by a Reduction/Conjugate Addition/Hydroxylation Sequence

Autor:	Rainer Kramer, Reinhard Brückner
Rok vydání:	2013
Předmět:	Sharpless epoxidation chemistry.chemical_classification Stereochemistry Organic Chemistry Grignard reaction Alcohol Polyene Oxaziridine Hydroxylation chemistry.chemical_compound chemistry Polyol Moiety Physical and Theoretical Chemistry
Zdroj:	European Journal of Organic Chemistry. 2013:6563-6583
ISSN:	1434-193X
Popis:	Epoxy alcohol anti-10, derived from a desymmetrizing Sharpless epoxidation (up to 97 % ee) of divinylcarbinol 9, provided the unsaturated 1,3-diol syn-11 upon treatment with RedAl®; syn-11 was converted into the α,β-unsaturated esters (E)- or (Z)-7b in three steps. Cu-promoted 1,4-addition of vinylmagnesium halides to the (E)-ester proceeded with diastereoselectivities of up to 91 % and Cu-catalyzed 1,4-additions with diastereoselectivities of up to 82 %. The potassium enolate of the major vinylation product syn-22b was hydroxylated by the Davis oxaziridine with perfect but unprecedented diastereoselectivity. The resulting hydroxy ester, α,βsyn,β,γsyn-32, furnished the “eastern moiety” building block 6 of the title compounds in three steps.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::a2ef633252f593349066309dc9e633ef https://doi.org/10.1002/ejoc.201300182 Zobrazit plný text záznamu Plný text ve formátu PDF Plný text ve formátu HTML
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