Solvent Effects in the Nucleophilic Substitutions of Tetrahydropyran Acetals Promoted by Trimethylsilyl Trifluoromethanesulfonate: Trichloroethylene as Solvent for Stereoselective C- and O-Glycosylations

Highly efficient α-C-sialylation promoted by (p-Tol)2SO/Tf2O with N-acetyl-5-N,4-O-oxazolidione protected thiosialoside as donor.

Based on a preactivation protocol with (p-Tol)2SO/Tf2O, a practical, straightforward, and high-yielding synthesis of α-sialyl C-glycosides was accomplished by coupling N-acetyl-5-N,4-O-oxazolidione protected thiosialoside with various trimethylsilyl enol ethers and allyltrimethylsilanes. High yields and excellent α-selectivities were obtained for the strong π-nucleophiles with large nucleophili...

TMSBr-mediated solvent- and work-up-free synthesis of α-2-deoxyglycosides from glycals

The thio-additions of glycals were efficiently promoted by a stoichiometric amount of trimethylsilyl bromide (TMSBr) to produce S-2-deoxyglycosides under solvent-free conditions in good to excellent yields. In addition, with triphenylphosphine oxide as an additive, the TMSBr-mediated direct glycosylations of glycals with a large range of alcohols were highly α-selective.

N-Trimethylsilyloxy-enamines as New Aldehyde Enolate Synthons: General, Efficient and Diastereoselective Aldol Reaction with Ketals and Acetals Induced by Trimethylsilyl Trifluoromethanesulfonate

Photolysis (A 185 nm) of Liquid Tetrahydropyran*

The main products of the 185 nm photolysis of neat liquid tetrahydropyran are pent-4en-l-ol (7) (0 = 0.40), 2-(5'-hydroxypentyl)tetrahydropyran (10) (0.21), valeraldehyde (6) (0.13), and pentan-l-ol (8) (0.08). These products are thought to be formed via the biradical '0(0112)40112, and/or through intramolecular (6, 7, 8) and intermolecular (10) photoreactions. In the case of 10, the probabilit...

Nano-SiO2/hexamethylenetetramine promoted synthesis of pyrano[2,3-c] pyrazoles under solvent-free conditions

In this study, the nano-SiO2/hexamethylenetetramine as a new basic heterogeneous nanocatalyst was prepared and used for the synthesis of pyranopyrazole via the four-component reaction. Various aldehydes, hydrazine hydrate, ethyl acetoacetate and malononitrile were reacted at room temperature under solvent-free and grinding conditions. The morphology and structure of nano-cat...