Oligosaccharides, one of the most abundant biopolymers, are involved in numerous biological processes. Although many efforts have been put in preparative carbohydrate chemistry, achieving optimal anomeric and regioselectivities remains challenging. Herein we describe an oxidative glycosylation method between anomeric stannanes and oxygen nucleophiles resulting in the formation of a C-O bond with consistently high anomeric control for glycosyl donors bearing a free C2-hydroxyl group. These reactions are promoted by hypervalent iodine reagents with catalytic or stoichiometric amounts of Cu or Zn salts. The generality of this transformation is demonstrated in 42 examples. Mechanistic studies indicate that the oxidative glycosylation is initiated by the hydroxyl-guided delivery of the hypervalent iodine and tosylate into the anomeric position, and results in excellent 1,2-trans selectivity. The unique mechanistic paradigm, high selectivities, and mild reaction conditions make this method suitable for the synthesis of oligosaccharides and for integration with other methodologies such as automated synthesis.

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Stereoselective oxidative glycosylation of anomeric nucleophiles with alcohols and carboxylic acids

Compounds including various oligomers of piperlongumine and/or piperlongumine analogues as well as certain piperlongumine analogues that exhibit improved toxicity to cancer cells are disclosed. Also provided are compositions that comprise the compounds, methods of making compositions comprising the compounds, methods of making the compounds, and the use of compounds in methods for treating cancer.

Compounds, Compositions, and Methods for Cancer Therapy

Highly enantioselective copper-phosphoramidite-catalyzed conjugate addition of dialkylzinc reagents to acyclic a, b-unsaturated imides

Stereoselective Synthesis of 2-Hydroxy-a-mannopyranosides from Glucal Donors.

A New Synthesis of L-Ascorbic Acid from D-Galactose.

A Novel Effective Transition Metal Based Salt-Catalyzed Azidolysis of 1,2-Epoxides.

2,5‐Dioxabicyclo(2.2.2)octane Ring Systems in the Tautomeric Forms of D‐lyxo‐Hexopyranosid‐2‐ulose, 1,5‐Anhydro‐D‐tagatose, and D‐lyxo‐ Hexodialdo‐1,5‐pyranosid‐2‐ulose Derivatives.

V. Di Bussolo

Papers

Highly enantioselective copper-phosphoramidite-catalyzed conjugate addition of dialkylzinc reagents to acyclic a, b-unsaturated imides

Stereoselective Synthesis of 2-Hydroxy-a-mannopyranosides from Glucal Donors.

A New Synthesis of L-Ascorbic Acid from D-Galactose.

A Novel Effective Transition Metal Based Salt-Catalyzed Azidolysis of 1,2-Epoxides.

2,5‐Dioxabicyclo(2.2.2)octane Ring Systems in the Tautomeric Forms of D‐lyxo‐Hexopyranosid‐2‐ulose, 1,5‐Anhydro‐D‐tagatose, and D‐lyxo‐ Hexodialdo‐1,5‐pyranosid‐2‐ulose Derivatives.