Alkylation of Enolate IonsThomas A Newton
Asymmetric induction in the alkylation of enolate anion with the optically active selenonium ionsindan derivativesMethyl phenyl selenide (I) is ethylated to form the racemic selenonium salt (IIIa) which is optically resolved via the D-camphor sulfonates.doi:10.1002/chin.198727142...
The more loosely coordinated sodium or potassium cations are preferable to the strongly coordinating lithium and magnesium ions. The preferred conditions for N-alkylation of pyrroles involve formation of the anion in liquid ammonia or DMSO. Appropriate bases are, respectively, sodium amide generated in...
On the basis of extensive reported studies, alkylation of aldehydes is not considered to be a generally useful synthetic transformation. Aldol condensations and Can-nizzaro—Tishchenko reactions1 typically reduce the yields of the desired alkylated aldehydes severely. Reactions of potassium enolates of ...
intermediate generated the ketone intermediate (C) and a new LDA. The easy enolization afforded the enolate intermediateD, providing the driving force of the reaction. The final ketone product was then obtained after the quench of the enolate intermediateDwith water. The protonation of intermediate...
The rates of alkylation show only a 10-fold range within the series and generally parallel the basicities of the enolate ions. Marked effects on acidity and alkylation rate which can be attributed to the presence of a cyclic structure are noted only for the five and six-membered ring systems...
There- by, ketone (R)-9 was obtained in 88%ee and 99% yield when the ligand (S,S)-8, which causes the allylpalladium inter- mediate to attack the enolate from its Si face, was used. This stereochemical outcome is plausibly explained by the simplified “mnemonic” illustration of the C...
A side-chain of a substituted aromatic compound is alkylated by reacting the aromatic compound with an alkylating agent in the presence of a catalyst. The catalyst comprises a restructured smectite clay to which basic ions are incorporated by ion-exchange. The restructuring of the smectite clay is...
CAS past decade?5 Hence, the ability to facilitate the highly diastereo— o2bof9yn and enantioselective propargylic alkylation of unstabilized ketone morpholinium ions prevents the shift of the H—atom to CB of the enolates or their equivalents with propargylic esters to directly and selectively ...
Conjugate addition of vinyl cuprate reagent50to α,β-unsaturated lactam49from thereface and subsequent trapping of the intermediate enolate with acetaldehyde provided alcohol52with good (8:1)diastereoselectivity(Scheme 8). The diastereoselectivity of thisaldol additionis in accord with a Zimmerman–Traxl...