The Total Synthesis and Structural Assignment of Hexaketide Xylarinol B and its C1′‐Epimer

Abstract

The total synthesis of two isomeric hexaketides isolated along with sordarial, whichh ave the proposed relative arabino and ribo configurations, has been executed. A Rh-catalyzed [2+ +2+ +2]-alkyne cyclotrimerization has been employed as the key reactiont oc onstruct the central dihydroisobenzofuran core. The absolute configurationo ft he xy-larinol Bh exaketide has been established as l-arabino.T his is the first natural product of this family for which the absolute configuration has been determined, and this can be extended to provide structural details of several of relatedh exaketides.[a] V. Mullapudi, C. V. Ramana Scheme1.Key retrosyntheticd isconnections for 1 and 2.TBS = tert-butyldimethylsilyl.Scheme2.To tal synthesis of (+ +)-xylarinol B( 1).

New Polyketides from the Marine-Derived Fungus Letendraea Sp. 5XNZ4-2

“…The known compound 8 was determined to be xylarinol by comparison of its NMR data with the reported literature [15]. Figure S7) revealed 7S and 9R configurations, identical to 5, and a 4R configuration different from 5, in 6.…”

“…The strain was static cultured at 28 °C for 30 days in 500 mL Erlenmeyer flasks (100 × 200 mL, a total of 20 L) each containing 200 mL of 1/2 PDB liquid media (100 g of potato extract, 17 g of artificial sea salt, and 10 g of dextrose in 1 L pure water). The known compound 8 was determined to be xylarinol by comparison of its NMR data with the reported literature [15].…”

Total Synthesis of (+)-Petromyroxol, (−)-iso-Petromyroxol, and Possible Diastereomers

“…As shown in Scheme 6 , the synthesis of compounds 1′ – 4′ started with the known epoxide 5′ , and the same protocols that were used for the syntheses of 1 – 4 ( Schemes 2 – 5 ) were adopted. 20 …”

DBU/AgOTf Relay‐Catalysis Enabled One‐Pot Synthesis of 1,3‐Dihydroisobenzofurans and Its Conversion to Indanones

“…1,3‐Dihydroisobenzofurans are a class of prominent substructure which widely present in numerous pharmaceuticals and natural products [1] . For example, xylarinol B, a nutritional sugar substitute that is most suitable for diabetics, has a rare 1,3‐dihydroisobenzofuran skeleton [1a] . In addition, some 1,3‐dihydroisobenzofuran derivatives can be used as inhibitors of a variety of biological enzymes, such as peptide deformylase, [1b] glutathione S‐transferase [1c] (Figure 1).…”