E. Difranco et al., TOTAL SYNTHESIS OF HALICHONDRINS - ENANTIOSELECTIVE CONSTRUCTION OF AHOMOCHIRAL TETRACYCLIC KLMN-RING INTERMEDIATE FROM D-MANNITOL, Tetrahedron letters, 34(20), 1993, pp. 3247-3250
An efficient strategy exploiting C2 symmetry and featuring diastereose
lective conjugate addition of Li2Me2CuCN to a gamma-alkoxy-alpha,beta-
unsaturated acylsilane and diastereoselective spiroketalization provid
es a key tetracyclic KLMN-ring intermediate for halichondrin B from D-
mannitol.