Merremoside D: De Novo Synthesis of the Purported Structure, NMR Analysis, and Comparison of Spectral Data

Abstract

The first synthesis of the purported structure of Merremoside D has been achieved in 22 longest linear steps. The de novo asymmetric synthesis relied on the use of asymmetric catalysis to selectively install all 21 stereocenters in the final compounds from commercially available achiral starting materials. Adiabatic gradient 2D NMR techniques (gHSQCAD, gHMBCAD, gH2BCAD, gHSQCTOXYAD, ROESYAD) were used to completely assign the structure of synthetic Merremoside D. Comparison of our assignments with the limited NMR data reported for natural Merremoside D allows for the tentative confirmation of its structure.

Denovo asymmetric synthesis of the mezzettiaside family of natural products via the iterative use of a dual B-/Pd-catalyzed glycosylation

“…In addition, slightly different chemical shifts are obtained depending on which solvent is used as the reference standard. This problem with carbohydrate natural products has been previously observed by us 15 and others. 16 By exercising with great care in the solvent ratios we were able to generate 13 C NMR spectra for nine of the ten mezzettiasides were the shifts fell within (+/−) 0.5 ppm.…”

Macrolide Core Synthesis of Calysolin IX Using an Intramolecular Glycosylation Approach

“…The most efficient approach to disaccharide part 3 began with the synthesis of jalapinolic ester 6 from undecyne and hexanal. Enantioselective reduction of the alkynone with ( S , S )‐Noyori catalyst resulted in the alcohol with high ee . Thus obtained aglycon was used for the one‐pot formation of β‐glycoside from 6‐deoxyglucal ( 7 ).…”

Glycosylation via Transition‐Metal Catalysis: Challenges and Opportunities

“…The versatile ketone and alkene functionality in 133 and 134 can be further functionalized to enable the de novo synthesis of complex oligosaccharides . This palladium‐catalyzed O ‐glycosylation reaction was later successfully applied to the de novo synthesis of a number of complex oligosaccharides and bioactive natural molecules bearing complex oligosaccharides, including trehalose analogues, daumone, homoadenosine, manno ‐disaccharide fragments of mannopeptimycin‐E, aza‐analogues of the glycosylated tyrosine portion of mannopeptimycin‐E, d ‐ and l ‐Swainsonine, digitoxin and digitoxigenin analogs, kaempferol glycoside SL0101 and its analogs, anthrax tetrasaccharide, trisaccharide portion of landomycin A, trisaccharide portion of PI‐080 and vineomycin B 2 , deoxyaltropyranoside, cleistrioside and cleistetroside natural products, disaccharide portion of SCH‐47554, cleistriosides, complex oligosaccharides, and merremoside D …”