Article révisé par les pairs
Résumé : Specific deuterium labelling, combined with 13C-NMR spectroscopy, has been used to study the course of the photocyclodehydrogenetions leading to hexa-, hepta-, octa- and nonahelicene. The case of heptahelicene is a good illustration of the scope and limitations of this technique in this particular field. © 1972.