Computational prediction of the enantioselectivity of a solid-state photoreaction

[GRAPHICS] To better understand the forces controlling chemical reactions in crystals, the absolute asymmetric photorearrangement of 4-m-chlorobenzyloxy-2-pyridone leading to the corresponding enantiomerically enriched (78% ee) beta-lactam was modeled computationally using a flexible minilattice consisting of a central reactant and 20 nearest and 72 next-nearest neighbors. The computational results predicted a preference for formation of the (R,R)-enantiomer, and this was verified experimentally by absolute configuration correlation studies.