CHEMISTRY OF CARBANIONS .15. STEREOCHEMISTRY OF ALKYLATION OF 4-T-BUTYLCYCLOHEXANONE

Alkylation of the enolate anion 1 of 4-t-butylcyclohexanone with triethyloxonium fluoroborate yielded a mixture of O-alkylated product and a mixture of approximately equal amounts of the stereoisomeric 2-ethyl-4-t-butylcyclohexanones. A comparable mixture of C-alkylated products was obtained from reaction of the enolate anion with ethyl iodide for short periods of time. Quenching the enolate anion 1 in a mixture of deuterium oxide and deuterioacetic acid yielded a mixture of the axial deuterio ketone (ca. 70%) and the equatorial deuterio ketone (ca. 30%). These results are interpreted as evidence that the transition states for alkylation and protonation have geometries resembling the enolate anion 1 rather than the products. © 1968, American Chemical Society. All rights reserved.