7-oxanorbornene cycloadducts. X-ray, molecular orbital and photoelectron spectroscopic study

Structural (X-ray and MP2(fc)/6-31G*) features of 1,4:5,8-diepoxynaphthalen es 1 and 2 are reported. The extent of endo bending of the olefinic hydroge ns is estimated from the calculated structures and compared with the X-ray data. The computed out-of-plane angles are 7.6 and 6.8 degrees in 1 and 2, respectively. Photoelectron spectroscopic data of diepoxynaphthalenes 1 and 2 and their higher analogue 3 are discussed and interpreted in terms of th rough-space and through-bond interaction of the oxygen lone pairs and their interactions with the olefinic pi-orbital.