New hindered isomers of 3-dehydroretinal (Vitamin A2)

Article abstract of DOI:10.1016/0040-4020(96)00355-9

The preparation of six new isomere (7-cis, 7,9-dicis, 7,11-dicis, 7,13-dicis, 7,9,11-tricis and 7,9,13-tricis) of 3-dehydroretinal (1, vitamin A₂), and their spectroscopic properties are reported. Because of the unexpected 1,7-H migration in photo-sensitized isomerization of the smaller building blocks in the dehydro-series, the introduction of the 7-cis geometry in the synthesis of new hindered isomers of 3-dehydroretinal required construction of this cis-double bond prior to that of the 3,4-double bond. Copyright