Sulfate esters, cyclic, preparation

Boronic esters of (R,R)-l,2-dicyclohexyl-l,2-ethanediol or pinanediol react with thionyl chloride and excess imidazole in acetonitrile on a borosilicate glass surface to form the corresponding cyclic sulfites of diols <20010M2920>. Similarly, cyclic sulfites and sulfates have been prepared from silicates of diols <1997TL4841>. 

Cyclic sulfates can even be prepared from diols containing acid-sensitive groups acetonide, silyloxy) by reaction with thionyl chloride and N(C2H5)3 followed by oxidation of the isolated sulfites with Ru04 (catalytic). After reactions with a nucleophile, the resulting sulfate esters can be hydrolyzed by water (0.5-1.0 equiv.) in THF catalyzed by H2S04. The use of a minimal amount of water is crucial for chemoselectivity.2... 

Most compounds of this type are cyclic sulfite and sulfate esters of aromatic 1,2-diols as well as anhydrides of aromatic 1,2-disulfonic acids. The simplest representatives with unsubstituted benzene rings are 1,3,2-benzodioxathiole 2-oxide (48) (catechol sulfite), the corresponding 2,2-dioxide (156) (catechol sulfate) and 2,1,3-benzoxadithiole 1,1,3,3-tetroxide (158) (1,2-benzenedisulfonic anhydride). Compound (48) was synthesized by refluxing catechol with thionyl chloride in the presence of pyridine. In a similar fashion, from 2-mercaptophenol 1,2,3-benzoxadithiole 2-oxide was prepared (81AG603). The dioxide (156) was obtained in two steps by reaction of catechol monosodium salt with sulfuryl chloride in benzene at 0-10 °C and subsequent reflux of the intermediate (155) in the presence of pyridine. 

Similarly, cyclic sulfite and cyclic sulfate esters of the corresponding 1,2-diamines have been named 1,2,5-thiadiazole 1-oxide (5) and 1,2,5-thiadia-zole 1,1-dioxide (6). In this chapter, emphasis is placed on cyclic sulfites and cyclic sulfates however, the synthetic preparation and nucleophilic transformations of cyclic sulfamidites and cyclic sulfamidates are also compared. 

This chapter will discuss methods for the preparation of esters, acid chlorides, anhydrides, and amides from carboxylic acids, based on acyl substitution reactions. Acyl substitution reactions of carboxylic acid derivatives will include hydrolysis, interconversion of one acid derivative into another, and reactions with strong nucleophiles such as organometallic reagents. In addition, the chemistry of dicarboxylic acid derivatives will be discussed, as well as cyclic esters, amides, and anhydrides. Sulfonic acid derivatives will be introduced as well as sulfate esters and phosphate esters. Finally, nitriles will be shown to be acid derivatives by virtue of their reactivity. 

Treatment of diethyl malonate and related compounds with 1,2-dihaloethane in the presence of base constitutes a classical method of cyclopropane synthesis296"300. The reaction can be conveniently carried out under PTC conditions. An improved method utilizing solid-liquid phase transfer catalysis has been reported298. The reaction of dimethyl or diethyl malonate with 1,2-dibromoalkanes except for 1,2-dibromethane tends to give only low yields of 2-alkylcyclopropane-l, 1-dicarboxylic esters. By the use of di-tm-butyl malonate, their preparations in satisfactory yields are realized (equation 134)297. The 2-alkylcyclopropane derivatives are also obtained from the reaction of dimethyl malonate and cyclic sulfates derived from alkane-1,2-diols (equation 135)301. Asymmetric synthesis... 

In the same vein as the cyclic sulfate activation of diols, cyclic sulfamidates have been prepared from 1,2- and 1,3-amino alcohols for the purpose of activating the carbinol toward nucleophilic attack [85-88]. (S)-Prolinol [85], A-benzyl serine t-butyl ester [86], and 2-(2-hy-... 

Phosphamides, A-Sulfates and Related Esters - 5- -,3-0-Cyclic phos-phamides have been prepared by reaction of 5-amino-5-deoxy-l,2-0-isopropyl-idene-a-D-xylofuranose with either phenylphosphonic dichloride or phosphoryl chloride, and their conformations determined. Chemo-selective -sulfation of 2-amino-2-deoxy-P-D-glucopyranose derivatives with a single free hydroxy-group was achieved with phenyl chlorosulfate followed by hydrolysis in aqueous NaHC03. ... 

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