Dihydroxylation Studies of Isoquinolinones: Synthesis of the EF-Ring of Lysolipin I

Inspired by the potent polycyclic xanthone antibiotic Lysolipin I, a general study on asymmetric dihydroxylation reactions of variously substituted isoquinolinones was performed. Different isoquinolinones were efficiently prepared, either by a Pomeranz-Fritsch type condensation or a Curtius rearrangement. Under a broad variety of conventional oxygenation procedures they proved very unreactive. However, either by suitable substitution of the appending aromatic ring or more forcing conditions a dihydroxylation could finally be performed, which allowed for synthesis of the EF-ring of Lysolipin I.

Scalable Synthesis of L-allo-Enduracididine: The Unusual Amino Acid Present in Teixobactin

A scalable synthesis of L-allo-enduracididine is achieved from commercially available (S)-glycidol in ten linear steps involving well established synthetic transformations. The synthetic route is flexible and can be used to synthesize all four diastereomers, by changing the stereochemistry of glycidol and Sharpless asymmetric dihydroxylation reagent.

Synthesis of the C19–C30 Bis-THF Fragment of Iriomoteolide-13a via Stepwise SN2 Cyclization and Intramolecular syn-Oxypalladation

The C19–C30 bis-THF fragment of the proposed structure of iriomoteolide-13a has been synthesized. The ω-mesyloxy-substituted stereotetrad possessing three continuous hydroxy groups was generated by anti-aldol reaction and asymmetric dihydroxylation (AD)...

Synthesis of the C19–C30 Bis-THF Fragment of Iriomoteolide-13a via Stepwise SN2 Cyclization and Intramolecular syn-Oxypalladation

The C19–C30 bis-THF fragment of the proposed structure of iriomoteolide-13a has been synthesized. The w-mesyloxy-substituted stereotetrad possessing three continuous hydroxy groups was generated by <i>anti</i>-aldol reaction and asymmetric dihydroxylation (AD). Upon heating in pyridine the stereotetrad underwent an S_N2 cyclization to form the C19–C22 THF ring. It was followed by an intramolecular <i>syn</i>-oxypalladation of the C28 chiral allylic alcohol to give the C23–C26 THF ring.

Synthesis of the C19–C30 Bis-THF Fragment of Iriomoteolide-13a via Stepwise SN2 Cyclization and Intramolecular syn-Oxypalladation

The C19–C30 bis-THF fragment of the proposed structure of iriomoteolide-13a has been synthesized. The w-mesyloxy-substituted stereotetrad possessing three continuous hydroxy groups was generated by <i>anti</i>-aldol reaction and asymmetric dihydroxylation (AD). Upon heating in pyridine the stereotetrad underwent an S_N2 cyclization to form the C19–C22 THF ring. It was followed by an intramolecular <i>syn</i>-oxypalladation of the C28 chiral allylic alcohol to give the C23–C26 THF ring.

Catalytic Asymmetric Osmium-Free Dihydroxylation of Alkenes

Asymmetric dihydroxylation of alkenes is one of the cornerstone reactions in organic synthesis, providing a direct entry to optically active vicinal diols, which are not only a subunit in natural products but also versatile building blocks. In recent years, considerable progress in catalytic asymmetric osmium-free dihydroxylation has been achieved. This short review presents a concise summary of the reported methods of catalytic asymmetric osmium-free dihydroxylation.1 Introduction2 Iron-Catalyzed Asymmetric syn-Dihydroxylation of Alkenes3 Manganese-Catalyzed Asymmetric syn-Dihydroxylation of Alkenes4 Palladium/Gold Bimetallic Nanocluster-Catalyzed Asymmetric syn-Dihydroxylation of Alkenes5 Enzyme-Catalyzed Asymmetric anti-Dihydroxylation of Alkenes6 Amine-Catalyzed Asymmetric Formal anti-Dihydroxylation of Enals7 Diselenide-Catalyzed anti-Dihydroxylation of Alkenes8 Molybdenum-Catalyzed Asymmetric anti-Dihydroxylation of Allylic­ Alcohols9 Phase-Transfer-Catalyzed Asymmetric Dihydroxylation of α-Aryl Acrylates10 Conclusion

Synthesis of Two Stereoisomers of Potentially Bioactive 13,19,20-Trihydroxy Derivative of Docosahexaenoic Acid

The C16–C22 fragment with the acetylene terminus was constructed through the asymmetric dihydroxylation of the corresponding olefin, while the 15-iodo-olefin corresponding to the C11–C15 part was prepared via the asymmetric transfer hydrogenation of the corresponding acetylene ketone followed by hydrozirconation/iodination. Both pieces were joined by a Sonogashira coupling, and the product was further converted into the title compound via a Wittig reaction with the remaining C1–C10 segment and Boland reduction using Zn with TMSCl.