Application of the selective ¹³C{¹H} nuclear Overhauser effect to structure elucidation of photoadducts derived from maleic anhydrides and thiophene

Abstract

Abstract The 13 C NMR spectra of a representative series of photoadducts derived from methylmaleic anhydrides and thiophene, containing the same basic carbon skeleton, were studied in order to establish a model for future structure elucidation of similar compounds. Selective heteronuclear 13 C{ 1 H} NOE was applied to stereochemical studies on the same compounds with the dual purpose of confirming previous assignments and to gain experience in the use of this technique, rarely applied in organic chemistry. The technique was employed in two different ways, by irradiating the selected proton resonance with and without modulation [ν m =½ J (CH)].