Tetrahedron

Experimental studies of the anomeric effect. Part VI. Ring inversion equilibria in cyclohexane, tetrahydropyran and piperidine rings substituted by a carbomethoxy or a …

H Booth, JM Dixon, KA Khedhair

Index: Booth, Harold; Dixon, J. Mark; Khedhair, Khedhair A. Tetrahedron, 1992 , vol. 48, # 29 p. 6161 - 6174

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Citation Number: 28

Abstract

The ring inversion equilibrium in carbomethoxycyclohexane is compared with those in 2- carbomethoxy-tetrahydropyran and 2-carbomethoxypiperidine through a variable temperature nmr study of the positions of equilibria. The derived ΔHoa→ e values (kcal mol− 1) of− 1.24 (cyclohexane),− 1.69 (tetrahydropyran) and− 0.54 (piperidine) can be rationalised in terms of competition between steric effects and endo-anomeric effects of ...