Designing an Apparently Orbital‐Symmetry‐Forbidden [3s,5s]‐Sigmatropic Shift through Transition‐State Complexation and Stereoelectronic Effects.

The [3s,5s]‐sigmatropic shift is an example of an orbital‐symmetry forbidden pericyclic reaction that is outcompeted by the allowed [3s,3s]‐sigmatropic shift. Density functional theory calculations are used to show that PdII‐complexed systems with strategically placed substituents engaging in key stereoelectronic effects can select for the [3s,5s] process, thereby outcompeting both orbital‐symmetry‐allowed [3s,3s]‐ and [3s,5a]‐shifts. [ABSTRACT FROM AUTHOR]