Giuseppe Capozzi

Phthalimidosulfenyl chloride. Part 5. Reaction with enolizable carbonyl compounds and synthesis of functionalized thiones.

Abstract β-Ketothio derivatives 4, prepared by reaction of phthalimidosulphenyl chloride with enolizable carbonyl compounds, afford, in presence of pyridine, unstable functionalized thiones which can be trapped with 1,3-dienes to give the corresponding cycloaddition products 8 and 9.

ortho‐Thioquinones, New Acceptors for the Stereoselective Synthesis of Aryl 2‐Deoxy‐O‐Glycosides

Unconventionalglycosylation: Under mild conditions, aryl 2-deoxy-α or -β-O-glycosides can be selectively obtained by capitalizing on ortho-thioquinones as new acceptors (scheme).

Thiiranes: one-pot synthesis from alkenes, and catalytic desulphurization

Abstract The reaction of bis(trimethylsilyl)sulphide with bromine at −78°C forms trimethylsilylsulphenyl bromide which reacts with alkenes to give thiiranes. Trimethylsilyl bromide and iodide catalytically desulphurize thiiranes to alkenes.

The reaction of ethanediyl S,S-acetals with halogens

Abstract Cyclic thioacetals and thioketals (1,3-dithiolanes) are reported to react smoothly with halogens in a 1:1 molar ratio, at room temperature in anhydrous carbon tetrachloride. The mechanistic aspects of the reaction are considered and evidence is shown of the intermediacy of monocationic rather than the previously postulated dicationic species in the cleavage reactions of 1,3-dithiolanes of aromatic ketones.

Silicon in organosulphur chemistry. Part 2. Synthesis of unsymmetrical disulphides

Abstract Unsymmetrical aryl- and alkyl- disulphides are prepared from silylsulphides and thiosulphinates or thiosulphonates. Silyl sulphinic esters are also obtained in the reaction of the thiosulphonates.

A novel stereo- and regio-controlled synthesis of 2-deoxy-α-O-aryl glucosides

Abstract The totally regio- and highly stereo-selective [4+2] cycloaddition of ortho-thioquinones 2a and 2b to substituted-D-glucals 3 represents a new and effective tool for the synthesis of 2-deoxy-α-O-aryl glucosides.

Phthalimidesulfenyl chloride part 8. Reaction with activated arenes: the first example of ortho-thioquinones generation☆

Abstract Phthalimidesulfenyl chloride 1 reacts with activated arenes 2a–g , to give monosubstituted derivatives 3a–g . Hydroxysulfenyl compounds 3a–d have been used as suitable source of α - oxothiones ( ortho -thioquinones) 4a–d , which act as heterodienes in 4+2 cycloaddition reactions.

α-Oxosulfines part 1: Reactivity of α-oxosulfines obtained from Retro Diels-Alder reaction of 1,4-oxathiin-S-oxides

Abstract Oxidation of 1,4-oxathiin derivatives 10–16 affords the corresponding sulfoxides 17–26 in high yield and good stereoselectivity. The oxathiin- S -oxides undergo a Retro Diels-Alder (RDA) reaction to form α-oxosulfines under very mild conditions. These reactive intermediates can be successfully trapped as dienophiles or as electron poor dienes in Inverse Electron Demand Diels-Alder reaction (IEDDA). The relationship between the structure of the starting sulfoxide, the geometry of the intermediate sulfine and the stereochemistry of the final cycloadduct have been tentatively correlated.

Silicon in organosulphur chemistry. Part 1. Synthesis of trisulphides

Abstract The reaction of bis(trimethylsilyl)sulphide with thiosulphinates and thiosulphonates in an inert solvent under neutral and mild conditions gives symmetrical alkyl- or aryl-trisulphides.

α-oxosulfines part 2: The first example of Ortho-thioquinone-S-oxides

Abstract Benzo-oxathiin- S -oxides 9b and 9c can undergo a Retro Diels-Alder (RDA) reaction to from ortho -thioquinone- S -oxides 12 and 11 . These hitherto unknown reactive intermediates can be successfully generated as function of the geometry of the starting sulfoxides and the type of aromatic system involved, and can be trapped as electron poor dienes or dienophiles.