A Glycal Approach to the Synthesis of Pregnane Glycoside P57

Liu, Chao; Ma, Yuyong; Pei, Chengfeng; Li, Wei; Yu, Biao

doi:10.1002/cjoc.201800331

Cited by 11 publications

(3 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…in CHCl 3 at −40°C; subsequent desilylation with TBAF at 60°C facilitated the purification of the resulting glycoside anomers, providing the proposed ecdysantheroside A ( 3a ) in satisfactory yield and stereoselectivity (97% over two steps, β/α = 3.9:1). It was known that the bulky TBDPS group at O 4 could enhance the β selectivity in glycosylation with cymarosyl donors via shielding the α face of the oxycarbenium intermediate ( 51 – 53 ). By the same token, coupling of d -cymarosyl o -hexynylbenzoate 18 with ecdysantherin ( 2 ), followed by desilylation with TBAF in the presence of acetic acid furnished ecdysoside A ( 5 ) (60% over two steps, β).…”

Section: Resultsmentioning

confidence: 99%

“…The convergent assembly of pregnane trisaccharides 4a and 6a called for glycosylation of the aglycones with the corresponding trisaccharide o-hexynylbenzoates (i.e., 19 and 20) (51)(52)(53). We screened various combinations of the gold(I) catalyst, solvent, and temperature for the coupling of aglycone 1 with trisaccharide donor 19 (see table S2 for details).…”

Section: Synthesis Of the Proposed Ecdysosides A (5) B (6a) And F (4a...mentioning

confidence: 99%

See 1 more Smart Citation

Merging total synthesis and NMR technology for deciphering the realistic structure of natural 2,6-dideoxyglycosides

Zhang,

Wu,

Cao

et al. 2024

Sci. Adv.

Self Cite

View full text Add to dashboard Cite

The structural identification and efficient synthesis of bioactive 2,6-dideoxyglycosides are daunting challenges. Here, we report the total synthesis and structural revision of a series of 2,6-dideoxyglycosides from folk medicinal plants Ecdysanthera rosea and Chonemorpha megacalyx , which feature pregnane steroidal aglycones bearing an 18,20-lactone and glycans consisting of 2,6-dideoxy-3- O -methyl-β-pyranose residues, including ecdysosides A, B, and F and ecdysantheroside A. All the eight possible 2,6-dideoxy-3- O -methyl-β-pyranoside stereoisomers (of the proposed ecdysantheroside A) have been synthesized that testify the effective gold(I)-catalyzed glycosylation methods for the synthesis of various 2-deoxy-β-pyranosidic linkages and lays a foundation via nuclear magnetic resonance data mapping to identify these sugar units which occur promiscuously in the present and other natural glycosides. Moreover, some synthetic natural compounds and their isomers have shown promising anticancer, immunosuppressive, anti-inflammatory, and anti-Zika virus activities.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Synthesis Of the Proposed Ecdysosides A (5) B (6a) And F (4a...mentioning

confidence: 99%

Merging total synthesis and NMR technology for deciphering the realistic structure of natural 2,6-dideoxyglycosides

Zhang,

Wu,

Cao

et al. 2024

Sci. Adv.

Self Cite

View full text Add to dashboard Cite

show abstract

“…15,16 Owing to the anomeric effect, glycosylation with 2-deoxy-or 2-azido-2-deoxy-glycosyl donors tends to give -glycosides as the major product. 3,4,10 Thus, extensive studies have been devoted into the construction of the more challenging -glycosides, [8][9][10][11][12][13][14] employing donors/intermediates via SN2/SN2-like pathway, [17][18][19][20] -face steric hindrance, [21][22][23][24] 2-halo participation, 25,26 -glycosyl lithium, 27,28 triflate acceptor, 29 2,3-anhydrosugar, 30 de novo synthesis, 31,32 oxidative activation with I2, 33 etc. However, their application in complex carbohydrate synthesis was usually case by case, hampered by narrow substrate scope, low efficiency, tedious steps, or harsh conditions.…”

mentioning

confidence: 99%

2-Diphenylphosphinoyl-acetyl as a remote directing group for the highly stereoselective synthesis of β-glycosides

Liu

Lin

Sun

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

The configuration of the anomeric glycosidic linkages is crucial for maintaining the biological functions and activities of carbohydrate molecules. However, their stereochemistry control in glycosylation represents one of the most challenging tasks in carbohydrate chemistry. In this report, the easily accessible 2-diphenylphosphinoyl-acetyl (DPPA) group was developed as a highly stereodirecting group for catalytic glycosylation via hydrogen-bond mediated delivery of the alcoholic acceptors. TMSOTf-catalyzed glycosylation with 6-O-DPPA glycosyl imidate donors displayed excellent β-selectivity and broad substrate scope, particularly applicable to synthesize the challenging β-configured 2-deoxy- and 2-azido-2-deoxy-glycosides from electron-deficient or bulky acceptors. Chemoselective removal of the DPPA group could be readily achieved under the mild catalysis of Ni(OTf)2, and further application was demonstrated in the synthesis of biologically important oligosaccharides, uronic acids, and 2,6-dideoxy-glycosides.

show abstract

Direct Synthesis of 2,6‐Dideoxy‐β‐glycosides and β‐Rhamnosides with a Stereodirecting 2‐(Diphenylphosphinoyl)acetyl Group

et al. 2022

Self Cite

View full text Add to dashboard Cite

Anomeric stereocontrol is usually one of the major issues in the synthesis of complex carbohydrates, particularly those involving β-configured 2,6-dideoxyglycoside and D/L-rhamnoside moieties. Herein, we report that 2-(diphenylphosphinoyl)acetyl is highly effective as a remote stereodirecting group in the direct synthesis of these challenging β-glycosides under mild conditions. A deoxy-trisaccharide as a mimic of the sugar chain of landomycin E was prepared stereospecifically in high yield. The synthetic potential was also highlighted in the synthesis of Citrobacter freundii O-antigens composed of a!] repeating unit, wherein the convergent assembly up to a nonasaccharide was realized with a strongly βdirecting trisaccharide donor. Variable-temperature NMR studies indicate the presence of intermolecular Hbonding between the donor and the bulky acceptor as direct spectral evidence in support of the concept of hydrogen-bond-mediated aglycone delivery.

show abstract

A Glycal Approach to the Synthesis of Pregnane Glycoside P57

Cited by 11 publications

References 35 publications

Merging total synthesis and NMR technology for deciphering the realistic structure of natural 2,6-dideoxyglycosides

Merging total synthesis and NMR technology for deciphering the realistic structure of natural 2,6-dideoxyglycosides

2-Diphenylphosphinoyl-acetyl as a remote directing group for the highly stereoselective synthesis of β-glycosides

Direct Synthesis of 2,6‐Dideoxy‐β‐glycosides and β‐Rhamnosides with a Stereodirecting 2‐(Diphenylphosphinoyl)acetyl Group

Contact Info

Product

Resources

About