Sulfides, dialkyl synthesis

HEXAHYDRO - 4a,5 - DIMETHYL - 2(3H) - NAPHTHALE-NONE and 2-TRIMETHYLSILYLOXY-1,3-BUTADIENE AS A REACTIVE DIENE DIETHYL trans -4-TRIMETHYL-SILYLOXY-4-CYCLOHEXENE-1,2-DICARBOXYLATE. Sulfur substitution also continues to be of high interest, and three preparations on sulfide synthesis are included BENZYL SULFIDE DIALKYL AND ALKYL ARYL SULFIDES NEOPENTYL PHENYL SULFIDE and UNSYMMETRICAL DIALKYL DISULFIDES sec-BUTYL ISOPROPYL DISULFIDE. 

Fluorinated and Ghlorfluorinated Sulfonic Acids. The synthesis of chlorinated and fluorinated sulfonic acids has been extensively reviewed (91,92). The Hterature discusses the reaction of dialkyl sulfides and disulfides, sulfoxides and sulfones, alkanesulfonyl haHdes, alkanesulfonic acids and alkanethiols with oxygen, hydrogen chloride, hydrogen fluoride, and oxygen—chloride—hydrogen fluoride mixtures over metal haHde catalysts, such as... 

Biocatalytic access to both antipodal sulfoxides was exploited in total syntheses of bioactive compounds, which is outlined in some representative examples. Biooxidation of functionalized dialkyl sulfides was utilized in the direct synthesis of both enantiomers of sulforaphane and some analogs in low to good yields and stereoselectivities (Scheme 9.27) [206]. This natural product originates from broccoli and represents a potent inducer of detoxification enzymes in mammalian metabolism it might be related to anticarcinogenic properties of plants from the cruciform family. All four possible stereoisomers of methionine (R = Me) and ethionine sulfoxides... 

Prochiral aryl and dialkyl ketones are enantioselectively reduced to the corresponding alcohols using whole-cell bioconversions, or an Ir1 amino sulfide catalyst prepared in situ.695 Comparative studies show that the biocatalytic approach is the more suitable for enantioselective reduction of chloro-substituted ketones, whereas reduction of a,/ -unsaturated compounds is better achieved using the Ir1 catalyst. An important step in the total synthesis of brevetoxin B involves hydrogenation of an ester using [Ir(cod)(py) P(cy)3 ]PF6.696... 

Enantiomerically pure sulfoxides play an important role in asymmetric synthesis either as chiral building blocks or stereodirecting groups [156]. In the last years, metal- and enzyme-catalyzed asymmetric sulfoxidations have been developed for the preparation of optically active sulfoxides. Among the metal-catalyzed processes, the Kagan sulfoxidation [157] is the most efficient, in which the sulfide is enantioselectively oxidized by Ti(OzPr)4/tBuOOH in the presence of tartrate as chirality source. However, only alkyl aryl sulfides may be oxidized by this system in high enantiomeric excesses, and poor enantioselectivities were observed for dialkyl sulfides. 

SULFIDE SYNTHESIS IN PREPARATION OF DIALKYL AND ALKYL ARYL SULFIDES NEOPENTYL PHENYL SULFIDE... 

SULFIDE SYNTHESIS IN PREPARATION OF UNSYMMETRICAL DIALKYL DISULFIDES sec-BUTYL ISOPROPYL DISULFIDE... 

Sodium toluene dispersion of, 55, 65 Sodium p-toluenesulfinate, 57, 103 Spiro[4 n] alkenones, 58, 62 Spiro[cyclopentane-l,l -indene] 55, 94 Squalene, 56, 116 Squalene, 2,3-epoxy, 56, 116 Stannic chloride, 56, 97 Steroids synthesis, 58, 85 E Stilbene, 55, 115,58, 73 z-Stilbene, 58, 133 Styrene, 56, 35,58, 43 Styrene glycol, 55, 116 Styrene glycol dimesylate, 55, 116 Succinic acid, 58, 85 Succinic anhydride, 58, 85 Sucunimide, 56, 50, 58, 126 Succimmide, Vbromo, 55, 28, 56, 49 SULFIDE CONTRACTION, 55, 127 Sulfide, dimethyl-, 56, 37 SULFIDE SYNTHESIS, 58, 143,58, 138 SULFIDE SYNTHESIS ALKYL ARYL SULFIDES, 58, 143 SULFIDE SYNTHFSIS DIALKYL SULFIDES, 58, 143 SULFIDE SYNTHESIS UNSYMMETRI-CAL DIALKYL DISULFIDES, 58, 147 SULFONYL CYANIDES, 57, 88 Sulfur tetrafluoride, 57, 51... 

The typical S-oxidation with BVMOs allows the formation of chiral sulfoxides from organic sulfides. This oxidation has received much interest in organic chemistry due to its use in the synthesis of enantiomerically enriched materials as chiral auxiliaries or directly as biologically active ingredients. This reaction has been studied extensively with CHMO from Adnetohacter showing high enantioselectivi-ties in the sulfoxidation of alkyl aryl sulfides, disulfides, dialkyl sulfides, and cychc and acyclic 1,3-dithioacetals [90]. CHMO also catalyzes the enantioselective oxida-hon of organic cyclic sulfites to sulfates [91]. 

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