We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Configurational Lability at Tetrahedral Phosphorus: syn/anti‐Isomerization of a P‐Stereogenic Phosphiranium Cation by Intramolecular Epimerization at Phosphorus.
- Authors
Tipker, Ryan M.; Muldoon, Jake A.; Pham, Daniel H.; Varga, Balazs R.; Hughes, Russell P.; Glueck, David S.; Balaich, Gary J.; Rheingold, Arnold L.
- Abstract
Tetrahedral main‐group compounds are normally configurationally stable, but P‐epimerization of the chiral phosphiranium cations syn‐ or anti‐[Mes*P(Me)CH2CHPh][OTf] (Mes*=2,4,6‐(t‐Bu)3C6H2) occurred under mild conditions at 60 °C in CD2Cl2, resulting in isomerization to give a syn‐enriched equilibrium mixture. Ion exchange with excess [NBu4][Δ‐TRISPHAT] (Δ‐TRISPHAT=Δ‐P(o‐C6Cl4O2)3) followed by chromatography on silica removed [NBu4][OTf] and gave mixtures of syn‐ and anti‐[Mes*P(Me)CH2CHPh][Δ‐TRISPHAT]⋅x[NBu4][Δ‐TRISPHAT]. NMR spectroscopy showed that isomerization proceeded with epimerization at P and retention at C. DFT calculations are consistent with a mechanism involving P‐C cleavage to yield a hyperconjugation‐stabilized carbocation, pyramidal inversion promoted by σ‐interaction of the P lone pair with the neighboring β‐carbocation, and ring closure with inversion of configuration at P.
- Subjects
EPIMERIZATION; NUCLEAR magnetic resonance spectroscopy; ION exchange (Chemistry); PHOSPHORUS; CATIONS; CARBOCATIONS
- Publication
Angewandte Chemie, 2022, Vol 134, Issue 1, p1
- ISSN
0044-8249
- Publication type
Article
- DOI
10.1002/ange.202110753