An Approach Toward the Bridged 14-Membered Carbon Macrocycle of Bielschowskysin

Relying on our previous achievements toward the a total synthesis of bielschowskysin, we herein report additional efforts to close the bridged tetradecane carbocyclic core of this marine diterpene. The key step of this strategy is an intramolecular alkylation between a cis‐substituted vinyl halide and a lactone that were accessed by a diastereoselective propargylation/hydrogenation sequence and palladium‐catalyzed carbonylation, respectively. Along efforts to close the tetradecane carbocyclic core of the marine‐derived diterpene bielschowskysin by using an intramolecular alkylation strategy, numerous advanced molecules have been accessed. This stereoselective approach to the natural product features a diastereoselective propargylation/hydrogenation sequence as well as palladium‐catalyzed carbonylation as additional key steps.