Synthesis of Diarylheptanoid Scaffolds Inspired by Calyxins I and J

γ,δ-Unsaturated
alcohols are prepared efficiently in
two steps from o-hydroxycinnamaldehyde. The TMSOTf-mediated
reaction of the γ,δ-unsaturated alcohols with aldehydes
creates two oxygen heterocycles and three new stereocenters in a single
pot. The approach is versatile, and by varying the boronic acid, Grignard
reagent, and aldehyde, different substituents may be introduced, while
use of a chiral base in the conjugate addition gives enantioenriched
products.