Total synthesis of (−)-eburnamonine and (+)-epi-eburnamonine from a chiral non-racemic 4,4-disubstituted γ-lactone

The total synthesis of (−)-eburnamonine and (+)-epi-eburnamonine was successfully achieved using a key chiral non-racemic 4,4-disubstituted γ-lactone 4 that was prepared via the Rh(II) carbenoid mediated tertiary C–H insertion reaction of a chiral non-racemic diazomalonate 5.