摘要:
                                Studies have been conducted on testing strategies for annulation of the two macrocyclic rings onto the central tricyclic nucleus of sarain A (1). In particular, methodology has been developed for introduction into the core of C-3' and C-3 substituents, which are necessary for construction of the "eastern" and "western" macrocyclic rings of I, respectively. Formation of the western ring has been successfully addressed via a ring-closing olefin metathesis strategy utilizing the Grubbs ruthenium catalyst. With this macrocyclization approach, a key intermediate lactam has been prepared which will be utilized in a total synthesis of the natural product.