Synthetic studies on the bryostatins: Preparation of a truncated BC-ring intermediate by pyran annulation

Article abstract of DOI:10.1021/ol050511w

(Chemical Equation Presented) A synthesis of a potential BC-ring subunit (C₉-C₂₇) for bryostatin 1, a remarkably potent anticancer agent, has been developed in 16 steps and 18% overall yield. The key features of this route include a BITIP-catalyzed asymmetric allylation reaction, chelation-controlled allylations, a hydroformylation reaction, and a pyran annulation reaction.