Asymmetric Synthesis of Gonytolide A: Strategic Use of an Aryl Halide Blocking Group for Oxidative Coupling

The first synthesis
of the chromanone lactone dimer gonytolide
A has been achieved employing vanadium­(V)-mediated oxidative coupling
of the monomer gonytolide C. An o-bromine blocking
group strategy was employed to favor para–para coupling and to enable kinetic resolution of (±)-gonytolide
C. Asymmetric conjugate reduction enabled practical kinetic resolution
of a chiral, racemic precursor and the asymmetric synthesis of (+)-gonytolide
A and its atropisomer.