Phosphorus-containing reagents

The Preparation of Halodeoxy Sugars Using Phosphorus-Containing Reagents... 

Other examples of the use of phosphorus-containing reagents for the synthesis of deoxyhalogeno sugars, by way of Arbusov-type reactions, are described in Section 11,5 (see p. 278). 

There are several methods for the conversion of alcohols into iodides using phosphorus-containing reagents. Two important reagents (Rydon reagents) are methyltriphenoxy-phosphonium iodide 6 and iodotriphenoxyphosphonium iodide 7, respectively formed... 

Studies of the synthesis of phosphorus-containing derivatives of cellulose fall into two groups phosphorylation of cellulose with derivatives of phosphoric acids and phosphorous acids, respectively. Until recently, most studies have been of derivatives of cellulose and phosphoric compounds. There are a few publications reporting the synthesis of esters of phosphorous acids and cellulose, but the properties of these compounds have not been studied at all. However, esters ctf phosphorous adds and cellulose can be used for the preparation ctf ters of phosphoric adds and cellulose, which cannot be obtained by direct synttesis (or only with difficulty) by the reaction of the hydroxyl groups of the cellulose macromolecule with phosphorus-containing reagents. 

A variety of phosphorus-containing reagents have been employed in sugar chemistry in the direct S,.,2 replacement of hydroxy groups mainly by halide ions [35]. Most of these reagents used a combination of triphenylphosphine with an electrophilic halogen source such as At-halosuccinimide [36,37], carbon tetrahalides [38-41], and more recently, tri-haloimidazole or iodine and imidazole [42-45] or related reagents [46J. The Mitsunobu... 

In addition to the phosphorus-containing reagents, other reagents, such as the Vilsmeier-Haack reagent [(Me2N =CHX)X ] [3], sulfuryl chloride [4] and diethylaminosulfur trifluoride (DAST) [5] have also been employed for direct replacement of hydroxyl groups in carbohydrates. 

Reaction of starch with polyphosphates or phosphorus containing reagents, which is utilized in paper, adhesives, and textiles. 

A review on the reaction of quinones with phosphorus-containing reagents, including phosphites, phosphinites, and phosphonites, has appeared. Another review has been published on the synthesis and reactivity of tervalent fluoro-alkoxy derivatives of phosphorus. ... 

This reaction can be used to convert a ketone into an alkene by forming a new C—C bond at the location of the carbonyl moiety. The phosphorus-containing reagent that accompHshes this transformation is called a phosphorane, and it belongs to a larger class of compounds called ylides. An ylide is a compound with two oppositely charged atoms adjacent to each... 

Several related reactions involve the use of phosphorus reagents. Alkyl halides can be made from the treatment of an alcohol with phosphorus halides, PX3 or PX5, as shown in Figure 7.44. Many of these phosphorus-containing reagents cause rearrangement, especially in secondary systems, and the stereochemical outcome, retention or inversion, depends on solvent and other reaction conditions. Accordingly, modifications have been worked out in recent years in order to avoid such stereochemical problems. 

The most common of the phosphorus-containing reagents are diazaphospholidines 48 or 1,3,2-dioxyphos-pholanes 49 (Figure 50.15) prepared by reacting phosphorus trichloride with enantiomerically pure diamines or diols. Reagents with a wide variety of diamines and diols... 

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