Abstract
The use of counterpoise substituents permitted the quantitative determination of the large equatorial preference of the 2-diphenylphosphinoyl group in 1,3-dioxane, ΔG°307K[P(O)Ph2] = -3.23 kcal/mol. This result contrasts strongly with the significant axial preference of the same group in the 1,3-dithiane ring (+1.0 kcal/mol). Nevertheless, evaluation of the different steric requirements in these heterocycles reveals that the magnitude of the OC-P(O) and S-C-P(O) anomeric effects in the sulfur and oxygen heterocycles is quite similar, close to 3 kcal/ mol.
| Original language | English |
|---|---|
| Pages (from-to) | 5191-5193 |
| Number of pages | 3 |
| Journal | Journal of Organic Chemistry |
| Volume | 54 |
| Issue number | 22 |
| DOIs | |
| State | Published - 1 Oct 1989 |
| Externally published | Yes |