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Phosphorus‐containing groups in analyses of carbon‐13 chemical shifts of 1‐hetera‐4‐cyclohexanones

1983; Wiley; Volume: 21; Issue: 7 Linguagem: Inglês

10.1002/omr.1270210711

0030-4921

Jerry Hirsch, Kenneth Banasiak,

Synthesis and Reactivity of Sulfur-Containing Compounds

Abstract The 13 C NMR chemical shifts of a series of phosphorinanes and the corresponding 4‐phosphorinanones have been evaluated using ‘double difference’ plots. Most of the compounds fit the same linear relationships for the carbons alpha and beta to the hetera group previously found for the analogous sulfur, oxygen and nitrogen six‐membered heterocycles, suggesting that these phosphorus compounds possess similar chair conformations. For the carbons gamma to the hetera group, the plots suggest that there are transannular interactions between the trivalent phosphine groups and the carbonyl group, similar to that previously observed for the sulfide group. In these 1‐hetera‐4‐cyclohexanones, transannular interactions appear whenever a lone pair of electrons on a second‐row heteroatom is present in the proper conformation for interaction with the carbonyl group.