Racemization and transesterification of alkyl hydrogeno-phenylphosphinates
Guilhem Javierre1, Rémy Fortrie2, Marion Jean1
1Aix Marseille Univ, CNRS, Centrale Marseille, iSm2, Marseille, France.
Abstract:
In this article, we explore, both theoretically and experimentally, the general reactivity of alkyl hydrogeno-phenylphosphinates with alcohols. We show that alcohol molecules act exclusively as nucleophilic species, and add to alkyl hydrogeno-phenylphosphinates, leading to pentacoordinated intermediates. These intermediates are shown to subsequently competitively undergo alcohol eliminations and/or Berry pseudorotations. This offers several possible routes for racemizations and/or alcohol exchange reactions. Transition standard Gibbs free energies predicted from DFT calculations for the overall alcohol exchange mechanism are shown to be compatible with those experimentally measured in case ethanol reacts with ethyl hydrogeno-phenylphosphinate (134.5∼136.0 kJ mol-1 at 78 °C). Graphical abstract ᅟ.
Related Concept Videos
Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Benzene to Phenol via Cumene: Hock Process
Aldehydes and Ketones to Alkenes: Wittig Reaction Mechanism
The reaction begins with the nucleophilic addition between a phosphorus ylide and the carbonyl compound. Due to its carbanionic character, phosphorus ylide acts as a strong nucleophile and attacks the electrophilic carbonyl group. This generates a charge-separated dipolar intermediate called betaine. The negatively charged oxygen atom and...
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
Electrophilic Addition to Alkynes: Hydrohalogenation
Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...


