Asymmetric Total Synthesis of Propindilactone G, Part 1: Initial Attempts towards the Synthesis of Schiartanes.

Our first-generation synthetic study towards the total synthesis of propindilactone G (1) and its analogues is reported. The key synthetic steps were an intramolecular Pauson-Khand reaction (PKR) and a vinylogous Mukaiyama reaction (VMAR). The stereoselective synthesis of the CDE ring moiety with an all-carbon quaternary center through a PKR was difficult, whilst a VMAR afforded a product with the opposite stereochemistry at the C20 position on the side chain.

Total synthesis of (±)-decinine via an oxidative biaryl coupling with defined axial chirality.

The total synthesis of (±)-decinine has been achieved. The key steps in the synthesis involved the formation of lasubine II via a gold catalyzed annulation of 1-(but-3-yn-1-yl)piperidine and the formation of the 12-membered ring of decinine (1) with complementary atropselectivity via a VOF3-mediated oxidative biaryl coupling reaction.