Synthesis of the dysiherbaine tetrahydropyran core utilizing improved tethered aminohydroxylation conditions

Application of asymmetric Sharpless aminohydroxylation in total synthesis of natural products and some synthetic complex bio-active molecules

This report illustrates the applications of Asymmetric Sharpless Aminohydroxylation (ASAH) in the stereoselective synthesis of vicinal amino alcohols as important intermediates in the total synthesis of complex molecules and natural products with significant biological activities. The ASHA allows the regio- syn-selective synthesis of 1,2-amino alcohols via reaction of alkenes with salts of N-halosulfonamides, -amides and -carbamates employing osmium tetroxide (OsO4) as an efficient catalyst. In this reaction, chirality is induced via the addition of dihydroquinine- and dihydroquinidine as derived chiral ligands.

Total Synthesis of Neodysiherbaine A via 1,3-Dipolar Cycloaddition of a Chiral Nitrone Template

The total synthesis of neodysiherbaine A was achieved via 1,3-dipolar cycloaddition of a chiral nitrone template with a sugar-derived allyl alcohol in the presence of MgBr₂·OEt₂. This cycloaddition constructed the C2 and C4 asymmetric centers in a single step. Then reductive cleavage, intramolecular S_N2 reaction of the tertiary alcohol, and oxidation of the primary alcohol afforded neodysiherbaine A.

From glycals to aminosugars: a challenging test for new stereoselective aminohydroxylation and related methodologies

The most relevant methods to access 1-, 2-, 3-amino or 1,2-diaminosugars starting from unsaturated carbohydrates are concisely reviewed; the given examples illustrate the great challenges offered to several stereoselective strategies.

Total synthesis of (-)-dysiherbaine

The enantioselective synthesis of (-)-dysiherbaine (1) has been established with efficiency via a unique synthetic strategy involving the desymmetrization of 2-substituted glycerol to install a quaternary chiral carbon, which induces further stereochemistry in the bicyclic perhydrofuropyran through mercuriocyclization and epoxidation.