1.2- Oxathiane 2,2-dioxides

Oxathiane dioxides lithiated 641 synthesis of 638, 647 Oxathiane oxides, synthesis of 352 Oxathiolane oxides, synthesis of 241 Oxaziridines 72, 254, 826 as optically active oxidizing agents 291 Oxazolidinones 826 Oxazolines 619, 788... 

When a mixture of p-anisaldehyde and dimethyl sulfone was treated with excess potassium t-butoxide in DMF at 60-65 °C, bis-unsaturated sulfone 277 was obtained. In the reaction at 50 °C using a small amount of base, the main product was a heterocyclic compound, i.e., 2,4-di-p-methoxyphenyl-l,4-oxathiane 4,4-dioxide 278358. 

The lithio-derivative derived from cyclohexyl phenyl sulfone underwent 1,2-addition to cyclohexenylideneacetaldehyde or cinnamaldehyde to give the corresponding / -hydroxysulfones387. Reactions of 2,2-dimethyl-4-lithio-1,3-oxathiane 3,3-dioxide 308... 

The filtrate is cooled to 0° in a refrigerator overnight. The resulting precipitate is filtered, giving cis- and trans-2,Q-diethoxy-l,4-oxathiane 4,4-dioxide as a white solid (42-46 g., 74-81%), m.p. 83-117° (Note 7). 

This procedure represents the first reported synthesis of cis- and further reaction product, 4//-l,4-thiazine 1,1-dioxide. A derivative of the latter, 3,5-diphenyl-4//-l, 4-thiazine 1,1-dioxide,... 

Only structures pertaining to the saturated 1,2-oxathiane 2,2-dioxides have been published. The preferred chair conformer is preserved in both polycyclic <1989AGE202, 1998CEJ1480, 1996CC431, 1994JOC3687> and spiro derivatives <1998EJO2073> with the sulfone oxygens in pseudoaxial and pseudoequatorial orientations. 

Using a general procedure for the careful fluorination of sulfur-containing compounds, 1,2-oxathiane 2,2-dioxide 16 can be successfully fluorinated by treating the sultone with a mixture of elemental fluorine and helium gas at —78 °C for 8h, after which the crude reaction product is collected and fractionated in cooled traps <1991IC789>. The perfluoro sultone, that resulted, was isolated and characterized by and NMR spectroscopy, and MS. 

Sultones react easily with amines and anilines <1989PHA294, 1989EJC259, 1987LA481> 1,2-oxathiin 2,2-dioxide derivatives 104 condensed to give the corresponding sultams 105 but 1,2-oxathiane 2,2-oxides 16 were cleaved by aniline or benzoylhydrazine derivatives to provide the corresponding sulfonic acids 106 (Scheme 25) <1993AFF256>. 

Similarly, using either sulfuric acid, the SOs/dioxane complex, or a solution of SO3 in chloroform/dioxane, 4,6-diphenyl-l,2-oxathiin 2,2-dioxide was obtained from phenyl acetylene <1999RJ0415>, 3,6-disubstituted-l,2-oxathiane 2,2-dioxides were obtained from allylphenol <2002RJ01210>, and 3,4-dihydro-6-phenyl-l,2-oxathiin-4-one 2,2-oxide was obtained from Ph-CO-CH2-COMe <1991CIL253>. 

Further, a 1,2-oxathiane 2,2-dioxide derivative was obtained as a by-product (15-25%) in the enantioselective synthesis of Oasomycin A <2007AG545> all efforts to suppress this side reaction were not successful, and the reaction products of the hexafluorobutadiene sulfotrioxidation (among the main products a 4,5-dihydro-l,2-oxathiin 2,2-dioxide derivative) were identified by F NMR spectroscopy <2007RJA424>. 

The heat capacity, Cp, a useful parameter in evaluating vaporization, sublimation, and fusion enthalpies with temperature, was determined by DSC measurements for 1,3-oxathiane 3,3-dioxide to be 148.1 2.6 J moC at... 

The apparent suppression of deprotonation at the a-carbon may be due its capto-dative nature. This carbon atom is bonded to both an acceptor (C=0) and a donor (Hal), the corresponding carbanion is destabilized by the donor substituent. In connection with this tendency is the selective silylation [215] of l,3-oxathian-3,3-dioxide at C-4. 

After conversion to unsaturated sulfonates through reaction with vinyl or allyl sulfonyl chlorides, both primary and secondary alkenols afford dihydro-1,2-oxathiane 2,2-dioxides through a Ru-catalysed RCM (Scheme 55) <06T9017>. 

Vinyl and allyl sulfonates derived from primary and seeondary alkenols and from propargylie alcohols undergo an RCM in the presence of Ru catalysts to give dihydro 1,2-oxathiane 2,2-dioxides <03SL667>. 

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