Merremoside D: De NovoSynthesisof the Purported Structure, NMR Analysis, and Comparison of SpectralData.

Thefirst synthesis of the purported structure of Merremoside Dhas been achieved in 22 longest linear steps. The de novoasymmetric synthesis relied on the use of asymmetric catalysis toselectively install all 21 stereocenters in the final compounds fromcommercially available achiral starting materials. Adiabatic gradient2D NMR techniques (gHSQCAD, gHMBCAD, gH2BCAD, gHSQCTOXYAD, ROESYAD)were used to completely assign the structure of synthetic MerremosideD. Comparison of our assignments with the limited NMR data reportedfor natural Merremoside D allows for the tentative confirmation ofits structure. [ABSTRACT FROM AUTHOR]