Modeling and experiment reveal an unexpected stereoelectronic effect on conformation and scalar couplings of alpha-aminoorganostannanes, with possible relevance to the tin-lithium exchange reaction
by Santiago, Marcelina; Low, Eddy; Chambournier, Gilles; Gawley, Robert E.
The solution conformation of N-methyl-2-(tributylstannyl)piperidines has been determined through the use of vicinal Sn-119-C-13 coupling constants, revealing a conformational distortion caused by an unexpected stereoelectronic effect in some cases. Specifically, the "equatorial" conformer is distorted into a half-chair, in which the nitrogen lone pair eclipses the C-Sn bond. This distortion, which "costs" approximately 1 kcal/mol, correlates with a conformational dependence of geminal Sn-119-N-15 couplings and a possible correlation with reactivity in the tin-lithium exchange reaction.
- Journal of Organic Chemistry
- Start Page
- 0022-3263; 1520-6904