Pi-sigma interactions: Experimental evidence and its consequences for the chemical reactivity of organic compounds

Abstract

The magnitude of π/σ interactions in nonplanar π systems and its dependence on the planarity, length and energy of the sigma frame is demonstrated by means of photoelectron supectroscopy. Its consequences for the reactivity of nonplanar π systems is discussed in the case of fragmentation reactions, light-induced [2+2]cycloaddition reactions, addition reactions of sesquinorbornene, 1, 6-methano[10]annulene, 1, 6-8, 13-bismethano[14]annulene and Diels Alder reactions with isodicyclopentadiene. © 1987 IUPAC