Inversion of Configuration at the Phosphorus Nucleophile in the Diastereoselective and Enantioselective Synthesis of P‐Stereogenic syn‐Phosphiranes from Chiral Epoxides

Nucleophilic substitution results in inversion of configuration at the electrophilic carbon center (SN2) or racemization (SN1). The stereochemistry of the nucleophile is rarely considered, but phosphines, which have a high barrier to pyramidal inversion, attack electrophiles with retention of config...

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Published inAngewandte Chemie Vol. 130; no. 18; pp. 5141 - 5145
Main Authors Muldoon, Jake A., Varga, Balázs R., Deegan, Meaghan M., Chapp, Timothy W., Eördögh, Ádám M., Hughes, Russell P., Glueck, David S., Moore, Curtis E., Rheingold, Arnold L.
Format Journal Article
LanguageEnglish
Published Weinheim Wiley Subscription Services, Inc 23.04.2018
Subjects
Chemistry
Configurations
Enantiomers
Epoxides
Inversion
Nucleophile Substitution
P-stereogene Zentren
Phosphine
Phosphines
Phosphirane
Phosphorus
Racemization
Reaktionsmechanismen
Stereochemie
Stereochemistry
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Summary:Nucleophilic substitution results in inversion of configuration at the electrophilic carbon center (SN2) or racemization (SN1). The stereochemistry of the nucleophile is rarely considered, but phosphines, which have a high barrier to pyramidal inversion, attack electrophiles with retention of configuration at P. Surprisingly, cyclization of bifunctional secondary phosphine alkyl tosylates proceeded under mild conditions with inversion of configuration at the nucleophile to yield P‐stereogenic syn‐phosphiranes. DFT studies suggested that the novel stereochemistry results from acid‐promoted tosylate dissociation to yield an intermediate phosphenium‐bridged cation, which undergoes syn‐selective cyclization. Nucleophile Substitution verläuft mit Inversion (SN2) oder Racemisierung (SN1) am Elektrophil, aber was ist mit dem Nucleophil? Reagieren P‐stereogene Phosphane als Nucleophile, wird die Konfiguration am Phosphoratom für gewöhnlich beibehalten. Die erste intramolekulare nucleophile Substitution mit Inversion am Phosphorzentrum ist für die diastereo‐ und enantioselektive Synthese von P‐stereogenen syn‐Phosphiranen von entscheidender Bedeutung.
ISSN:0044-8249
1521-3757
DOI:10.1002/ange.201801427