Oxygen-bonded Derivatives

0-Bonded carbohydrate complexes of platinum-group metals have been comprehensively reviewed, as has the dibutyltin-mediated selective derivatization of compounds with three or more hydroxy groups. An intermolecular migration 

A series of 3,4-di-O-diarylphosphinite derivatives of fructose have been prepared as potential chiral ligands for Ni(0) complexes, and the reaction of l,2 5,6-di- 9-isopropylidene-a-D-glucofuranose with chlorophosphines (ClPPr R, R = Ph, Bu ) gave 3-0-phosphinite diastereomers, the ratio of which depended on the base used in their formation. Treatment of an anomerically unprotected aldo-pyranose with. /V,iV-diisopropylchlorophosphoramidite has generated the four diastereomers of the glycosyl phosphoramidite.  

Organotin ether derivatives continue to be utilized in the regioselective acylation and alkylation of carbohydrates. The 3-O-acylation of benzyl a-L-lyxopyranoside used the dibutylstannylene method while a polymer supported aryl(butyl)tin dichloride reagent has been used catalytically in the selective 6-0- 

The diphenylphosphono compound (10) has been made from the corresponding alcohol by use of the corresponding chloride and used as a ligand in a rhodium complex for asymmetric hydrogenation of alkenes,and the cyclic dioxytriphenylphosphoranes (11) and (12) 

The complex (13) is effective for the asymmetric reduction of alkyl aryl ketones and hindered dialkyl ketones, acetophenone, for example, affording (R)-1-phenylethanol with 78% enantiomeric excess, and t-butyl phenyl ketone being reduced stereospecificallyThe 

Partial esterification of the 2, 3 -stannylene derivative of the 6,5 -anhydronucleoslde (1 ) gave the 2- and 3-trlflates (15) and (16) in the ratio 9 1. With lithium chloride in HMPA both gave the 6,3 -anhydrlde (17), indicating that a triflate migration had 

An extensive range of cationic complexes have been described. 

Studies of the interaction between D-ribose and D-arabinose with 2+ 

The phosphitylation of D-mannose with phosphorous triazolides has afforded primarily the mannofuranose 2,3,6-O-phosphite 12. The complexes formed separately between o-fructose and L-sorbose with 1,10-phenanthroline and Co(III) ions have been characterised, while composites prepared by the reaction of simple sugars with tetraethoxysilane and water have been shown to be capable of resolving racemic cobalt and chromium ion complexes. Sodium alkoxide salts of free sugars have been treated with ferric chloride to give iron-sugar complexes and five-fold deprotonated D-mannose forms dinuclear metalates [X2(P-D-Man-/)2] of trivalent (X = Fe, V, Cr and Al) with O-1,2,3,5 and 6 involved in complexation.  

A study of the selectivity of metal chelate-directed benzoylation of sucrose dianion, relative to unchelated sucrose anions, was conducted as part of a study on new synthetic approaches to the high potency sweetner sucralose. Ionic complexes of sucrose with various metal ions in DMF reacted at low temperature with benzoic anhydride. Cobalt and manganese salts directed esterification mostly to the 3 -OH of the fructose.  

Molecular modelling calculations have been used to study the interactions between D-talopyranose, D-talofuranose and Pb and ions in the gas phase. In aqueous solutions Pb ions form carbohydrate complexes with both forms of the sugar whereas Hg ions do not. The calculations implied that the reverse ought to be true.  

Some O-carboxymethyl and O-carboxyethyl derivatives of carbohydrates have been prepared and their complexation with Ca ions in aqueous solution has been studied.  

The tungstate and molybdate complexes of D-gtycero-D-marmo-heptitol, d-gfycero-D-gu/o-heptonate, and a number of aldoses and ketoses containing the fyxo or marmo configuration have been characterized using C- and NMR methods. 

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Polyether. A polymer in which the repeating unit includes a carbon-oxygen bond derived from aldehydes, epoxides, poly alcohols or similar materials (Refs 1 4a). 

Carbon-bonded Phosphorus Derivatives Other Carbon-bonded Derivatives Oxygen-bonded Derivatives... 

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