An ester modification of this reaction was improved by the use of bis (2,2,2-trifluoroethyl) groups, KHMDS and crown ethers.
An ester modification of this reaction was improved by the use of bis (2,2,2-trifluoroethyl) groups, KHMDS and crown ethers. A related reaction that gives the opposite stereoselectivity can employ a benzothiazole derivative that exploits the Smiles rearrangement; that reaction's product is formed following reduction with sodium or samarium iodide and begins with the reaction of phenyl sulfonate derivatives. Interconversion between possible stereochemistries in this reaction's intermediate occurs by the mechanism described by Maryanhoff and Reitz. One cold-temperature modification of this reaction uses phenyllithium and hydrochloric acid to convert to the threo betaine intermediate. The reagent needed is prepared by the SN2 substitution of an alkyl halide with triphenylphosphine, followed by deprotonation by base. This reaction effectively carries out a metathesis that requires a four-membered intermediate that greatly favors the formation of an oxygen-phosphorus double bond. Its ester modification, improved by Gennari and Still, is the Horner-Wadsworth-Emmons reaction, and that related reaction using sulfones is named for Julia. For 10 points, name this reaction, which forms an alkene from a carbonyl.
An ester modification of this reaction was improved by the use of bis (2,2,2-trifluoroethyl) groups, KHMDS and crown ethers.
{Wittig} reaction [prompt by {saying} “{that's} the {aforementioned related reaction}” on {Julia olefination}; prompt by {saying} “{that's} the {ester modification}” on {Horner}-{Wadsworth}-{Emmons reaction}]