Synthesis and conformational analysis of a novel carbohydrate-fused bis-crown ether: crown-CyPLOS

A novel sugar-based macrocycle consisting of a phosphate-linked 12-membered disaccharide ring (cyclic phosphate-linked oligosaccharide, CyPLOS), fused to two 18-crown-6 ether residues, is here described. The synthesis of the target compound has been accomplished in 23% overall yield for 11 reaction steps, exploiting phosphoramidite chemistry for the dimerization and a classical phosphotriester methodology for the cyclization reaction. NMR-based conformational analysis studies have been carried out on the fully deprotected macrocycle, showing a characteristic arched-structure with C₂-symmetry.