Photocyclization of 2-azabicyclo[3.3.0]octane-3-carboxylate derivatives: induced and noninduced diastereoselectivity.

The decarboxylative photocyclization of potassium 2-azabicyclo[3.3.0]octanoate ethylene-linked to phthalimide leads to a mixture of two diastereoisomeric products. The overall noninduced diastereoselectivity is remarkably high, indicating a preference of spin−orbit coupling controlled 1,7-biradical combination process. Memory of chirality vanished due to free rotation about the connecting spacer bonds.