Nucleosides arylboronic acids

An N-heterocyclic carbene ligand, formed from l,3-bis-(2,4,6-trimethylphenyl)-3//-imidazol-l-ium chloride and cesium carbonate, with dipalladium tris(dibenzylideneacetone) gave excellent yields (93-96% yields) in the Suzuki coupling of 2-chloropurines and arylboronic acids in anhydrous dioxane <2001TL8751>. The combination of an imidazolium-carbene and nickel(O) bis(cyclooctadiene) formed a catalyst capable of insertion into the C-F bond of 6-fluoropurine nucleosides (Scheme 35) <20050L1149>. 

From the known, differential complexing between boronic acids and polyhydroxy compounds, it follows that carbohydrate mixtures may be separated by column-chromatographic methods that exploit the differences. Nucleoside and nucleotide boronates have been separated on columns of anion-exchange resins,90 and sugars and alditols have been shown to be differentially retained on such resins in the sulfonated phenylboronic acid form,64 but perhaps the best uses of column chromatography in this connection have incorporated the resolving powers of insoluble polymers to which boronic acid groups have been covalently bonded. Such insoluble forms of boronates have been synthesized either by substitution of polysaccharide derivatives, or by polymerization of suitable arylboronic acids. 

A series of new a-nucleophiles (738) has been synthesised, and their ability to efficiently and selectively cleave the P-S bond of organo-phosphorus nerve agents (737), has been evaluated. This reaction led to the new non-toxic phosphonic acid (739) and aminothiol (740) (Scheme 187). ° A series of novel pyrimidine based, acyclic nucleoside phosphonates (742), has been prepared, using the Liebeskind-Srogl cross-coupling protocol involving highly functionalised 2-(methylsulfanyl)pyrimidines (741) and various arylboronic acids (Scheme 188). " ... 

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