Identification and Characterization of the Major Photoadducts Formed Between 1-Phenyl-1,3-5-heptatriyne and undecylenic Acid Methyl Ester

Abstract

The near-UV induced photoreactions of 1-phenyl-1,3,5-heptatriyne (PHT) with undecylenic(10-undecenoic) acid methyl ester (UAME) and 1-hexene have been investigated in n-hexane. Four major photoadducts have been isolated in both cases and purified by normal and reverse phase liquid chromatography. The structures of these adducts were determined by mass, UV absorption, FT-IR, H-1- and C-13-NMR spectral analyses, one- and two-dimensional nuclear Overhauser effect studies, and H-1-H-1 homo-correlation spectroscopy. All the data indicate that the adducts are cyclobutenes resulting from the [2 + 2] photocycloaddition of PHT to UAME and 1-hexene.