The photochemical transformations of a series of spriocyclopropyl ketones (1–4) have been investigated in dilute n-hexane solutions. Spirocyclopropyl ketones 1 and 2 give mainly the'Type I'photoproducts of cycloalkanones, ie, 1-(2′-propenyl) cyclopropanecarboxaldehyde (5, 34%) and 1-(3′-butenyl) cyclopropanecarboxaldehyde (7, 37%), respectively, in marked contrast to the usual photochemical cleavage of ...