Rearrangement reactions sulfur trifluoride

When the 2-hydroxy group of a monosaccharide reacts with (diethylamino)sulfur trifluoride (DAST), quantitative and stereoselective rearrangements are observed (K.C Nico-laou, 1986). This reaction may simultaneously introduce fluorine to C-1 and a new oxygen, sulfur, or nitrogen residue to C-2 with inversion of configuration. 

Alkylphenol. Alkylphenol is a common surfactant intermediate used to produce alkylphenol ethoxylates. Phenol reacts with an olefin thermally without a catalyst but with relatively poor yields. Catalysts for the reaction include sulfuric acid p-toluene sulfonic acid (PTSA), strong acid resins, and boron trifluoride (BF3). Of these, strong acid resins and BF3 are mostly widely used for the production of surfactant-grade alkylphenols. The most common alkylphenols are octylphenol, nonylphenol, and dodecylphe-nol. Mono nonylphenol (MNP) is by far the most common hydrophobe. It is produced by the alkylation of phenol with nonene under acid conditions. All commercially produced MNP is made with nonene based on propylene trimer. Because of the skeletal rearrangements that occur during propylene oligomerization, MNP is a complex mixture of branched isomers. 

Sulfides are selectively fluorinated a to the sulfur atom via a reaction similar to the Pummerer rearrangement (Table 2). The fluorination wa.s originally achieved by the direct fluorination of sulfides with xenon difluoride.This reaction is proposed to occur by initial oxidative fluorination of the sulfide to give an unstable sulfur(IV) difluoride of type 1, followed by loss of hydrogen fluoride to give intermediate 2, followed by fluorine transfer to give the a-fluoro sulfide. This fluorination has also been achieved with diethylaminosulfur trifluoride (DAST) in the absence or presence of catalytic amounts of antimony(III) chloride (see Vol. ElOa, pp 421-423). ... 

Cava and Sehlessinger have reported the synthesis of 1,2,3-triphenyl-isoindole (65) in 78% yield from 1,3-diphenylisobenzofuran (68) by reaction with thionylaniline (69) and boron trifluoride.61 The mechanism proposed for this remarkable transformation involves rearrangement of the adduct (70) derived from thionylaniline and the isobenzofuran, to the tricyclic intermediate (71). This presumably collapses to the S-sultam (72), which yields the isoindole (65) upon extrusion of sulfur dioxide. Loss of sulfur dioxide, both from S-sultones and unsaturated S-sultams, is well documented.62 63... 

Discovery of the dienone-phenol rearrangement of quinol acetates has made possible the synthesis of dihydric phenols that were difficult of access by other routes. The starting materials are obtained from phenols and lead tetraacetate, and with acetic anhydride and sulfuric acid (Thiele acetylation) or with boron trifluoride in ether they give, respectively, di- and mono-acetyl derivatives of resorcinol or hydroquinone.309 When treated with lN-sodium hydroxide, 0-quinol acetates of type (1) undergo nucleophilic addition of an OH" ion, giving resorcinol derivatives (2).310 Occurrence of the reaction is considered... 

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