Glycosyl Dithiocarbamates: β-Selective Couplings without Auxiliary Groups

Glycosyl Dithiocarbamates: β-Selective Couplings without Auxiliary Groups

In this article, we evaluate glycosyl dithiocarbamates (DTCs) with unprotected C2 hydroxyls as donors in β-linked oligosaccharide synthesis. We report a mild, one-pot conversion of glycals into β-glycosyl DTCs via DMDO oxidation with subsequent ring opening by DTC salts, which can be generated in situ from secondary amines and CS2. Glycosyl DTCs are readily activated with Cu(I) or Cu(II) trifla...

FEM-BEM Couplings without Stabilization

Selective Radical-Radical Cross-Couplings: Design of a Formal β-Mannich Reaction.

A direct β-coupling of cyclic ketones with imines has been accomplished via the synergistic combination of photoredox catalysis and organocatalysis. Transient β-enaminyl radicals derived from ketones via enamine and oxidative photoredox catalysis readily combine with persistent α-amino radicals in a highly selective hetero radical-radical coupling. This novel pathway to γ-aminoketones is predic...

Heavy Metal Removal Using Dithiocarbamates

ajor emphasis is placed today on treating plating solutions and rinsewater to reduce the concentration of toxic metals to below established limits prior to discharge or water reuse. Available technology is adequate for partial treatment of most wastewater; however, new technology is needed to scavenge heavy metals from complexed or chelated compounds in rinsewater. Several report^^-'^ from this...

Stereoselective Synthesis of α- and β-l-Ara4N Glycosyl H-Phosphonates and a Neoglycoconjugate Comprising Glycosyl Phosphodiester Linked β-l-Ara4N

Stereoselective synthesis of variably protected α- and β-l-Ara4N glycosyl H-phosphonates as key intermediates in the syntheses of β-l-Ara4N-modified LPS structures and α-l-Ara4N-containing biosynthetic precursors is reported. A facile one-pot approach toward β-l-Ara4N glycosyl H-phosphonates includes anomeric deallylation of protected 4-azido β-l-Ara4N via terminal olefin isomerization followed...