Monitoring structural transformations in crystals. Part 10. monitoring molecular and crystal structures during a yang photocyclization reaction - Comparative studies

Structural changes in a crystal, brought about by the Yang photocyclization of the 2-(4-carboxybenzoyl)-2-methyl-endo-bicyclo[2.1.1]hexyl salt with (S)-(-)-l-phenylethylamine, were monitored by means of X-ray structure analysis. The changes taking place in the reaction centre, as well as changes in molecular orientation and cell constants are discussed. Analysis of the geometrical parameters describing the reaction centre enabled an evaluation of the possibility of formation of the opposite enantiomer in a crystal. The results are compared with data for other intramolecular photochemical reactions.