Synthesis of the Aryltetralin Lignan Skeleton via the Prins Reaction

Article abstract of DOI:10.1021/jo00157a017

Reaction of a 1,4-diaryl-1-butene (7) with paraformaldehyde and the appropriate alkylaluminum halide generates the cation 8, via addition of formaldehyde to the double bond, which cyclizes to give the aryltetralin 9.Reaction of 1,4-diphenyl-2-butene (6a) with paraformaldehyde and methylaluminum sesquichloride gives the ene adduct 5a, which reacts further, analogously to 7, to give 4a which possesses the aryltetralin lignan skeleton.