Efficient Conversion of Carbohydrates into 1-C-Alditols: Application to the Synthesis of Chiral γ-Substituted Butenolides and Bicyclic Alkaloid Analogues

“Cut and Paste” Processes in the Search of Bioactive Products: One-Pot, Metal-free O-Radical Scission-Oxidation-Addition of C, N or P-Nucleophiles

Hypervalent iodine reagents have been applied in many metal-free, efficient synthesis of natural products and other bioactive compounds. In particular, treatment of alcohols, acetals and acids with hypervalent iodine reagents and iodine results in O-radicals that can undergo a β-scission reaction. Under these oxidative conditions, derivatives of amino acids, peptides or carbohydrates are converted into cationic intermediates, which can subsequently undergo inter- or intramolecular addition of nucleophiles. Most reported papers describe the addition of oxygen nucleophiles, but this review is focused on the addition of carbon, nitrogen and phosphorous nucleophiles. The resulting products (nucleoside and alkaloid analogs, unnatural amino acids, site-selectively modified peptides) are valuable intermediates or analogs of bioactive compounds.

Iron-Catalyzed Radical Cleavage/C-C Bond Formation of Acetal-Derived Alkylsilyl Peroxides

A novel radical-based approach for the iron-catalyzed selective cleavage of acetal-derived alkylsilyl peroxides, followed by the formation of a carbon-carbon bond is reported. The reaction proceeds under mild reaction conditions and exhibits a broad substrate scope with respect to the acetal moiety and the carbon electrophile. Mechanistic studies suggest that the present reaction proceeds through a free-radical process involving carbon radicals generated by the homolytic cleavage of a carbon-carbon bond within the acetal moiety. A synthetic application of this method to sugar-derived alkylsilyl peroxides is also described.

Synthesis and glycosidase inhibition of conformationally locked DNJ and DMJ derivatives exploiting a 2-oxo-C-allyl iminosugar

The synthesis and glycosidase inhibition profile of a series of bicyclic analogs of DNJ and DMJ displaying a similar hydroxyl pattern and a distinct conformation is described.

Metal-free, one-pot conversion of proline derivatives into 2-aryl-3-iodo pyrrolidines by a sequential scission-iodination-arylation process

The metal-free, direct conversion of readily available proline derivatives into 2-aryl-3-iodopyrrolidines is carried out under mild conditions and in good yields, using a sequential radical decarboxylation-oxidation-iodination-arylation reaction. These iodinated pyrrolidines are valuable precursors of other compounds. For instance, they can be cyclized to tricyclic compounds or undergo dehalogenation to 2-aryl-2,5-dihydro-1H-pyrroles, which are iminosugar and 2-arylpyrrole precursors. This process provides a short pathway to a variety of alkaloid and drug analogues of potential pharmaceutical interest.