3. Synthesis of Unsaturated Lactone Moieties by Asymmetric Hetero-Diels-Alder Reactions with Binaphthol Titanium Complexes
M. Quitschalle, M. Christmann, U. Bhatt, M. Kalesse
Natural products like ratjadone and callystatin A contain an α,β-unsaturated lactone moiety which adds to the biological activity of these compounds. Here we report a rapid and practical access to lactone precursor 3 by an asymmetric hetero Diels–Alder reaction as the key step and its subsequent transformation into a suitable building block 4.