Convergent synthesis of BCDEF ring system of maitotoxin

Abstract Convergent synthesis of the BCDEF ring system of maitotoxin was achieved in 10 steps via Suzuki–Miyaura coupling of an enol phosphate corresponding to the B ring derived from L-ribose in 6 steps and an exo-olefin prepared from the DEF ring in 5 steps. Although initial attempts to obtain an O,S-acetal were unsuccessful, giving a bicyclic O,S-acetal as a byproduct, protecting group manipulation and optimization of reaction conditions solved the problem to afford the desired O,S-acetal as the major product, which was converted to the BCDEF ring via introduction of the angular methyl group.