51 research outputs found
Atropselective syntheses of (-) and (+) rugulotrosin A utilizing point-to-axial chirality transfer
Chiral, dimeric natural products containing complex structures and interesting biological properties have inspired chemists and biologists for decades. A seven-step total synthesis of the axially chiral, dimeric tetrahydroxanthone natural product rugulotrosin A is described. The synthesis employs a one-pot Suzuki coupling/dimerization to generate the requisite 2,2'-biaryl linkage. Highly selective point-to-axial chirality transfer was achieved using palladium catalysis with achiral phosphine ligands. Single X-ray crystal diffraction data were obtained to confirm both the atropisomeric configuration and absolute stereochemistry of rugulotrosin A. Computational studies are described to rationalize the atropselectivity observed in the key dimerization step. Comparison of the crude fungal extract with synthetic rugulotrosin A and its atropisomer verified that nature generates a single atropisomer of the natural product.P50 GM067041 - NIGMS NIH HHS; R01 GM099920 - NIGMS NIH HHS; GM-067041 - NIGMS NIH HHS; GM-099920 - NIGMS NIH HH
Skeletal Toxicity Associated with Chronic Ethanol Exposure in a Rat Model Using Total Enteral Nutrition
Vaststellen van verkoopprijzen, bewaken van kosten en waarderen van voorraden bij productiebedrijven die geen standaardkostprijzen gebruiken: een exploratief onderzoek
Vaststellen van verkoopprijzen, bewaken van kosten en waarderen van voorraden bij productiebedrijven die geen standaardkostprijzen gebruiken: een exploratief onderzoek
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