Unsaturated sulfones compounds

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. 

A highly efficient construction of the steroidal skeleton 166 is reported by Kametani and coworkers111 in the intramolecular Diels-Alder reaction of the a, jS-unsaturated sulfone moiety of 165 (equation 117). Thus, when the sulfone 165 is heated in 1,2-dichlorobenzene for 6h, the steroidal compound 166 can be obtained in 62% yield. The compound 166 produces estrone (167) by elimination of benzenesulfinic acid and subsequent hydrogenation of the formed double bond. The stereoselectivity of the addition reflects a transition state in which the p-tosyl group occupies the exo position to minimize the steric repulsion between methyl and t-butoxy groups and the o-quinodimethane group as shown in equation 117. 

There is generally little or no competition from 1,2 addition (to the C=0). However, when R is allylic,l,4 addition is observed with some substrates and 1,2 addition with others. The compound R2CuLi also add to a,P-unsaturated sulfones but not to simple aP-unsaturated nitriles. Organocopper reagents RCu (as well as certain R2CuLi) add to ocP-unsaturated and acetylenic sulfoxides. ... 

Conjugation of the 7t-electrons of the carbon-carbon double bond with the LUMO sulfur 3d-orbitals would be expected to stabilize the Hiickel 4n -I- 2 (n = 0) array of n-electrons in the thiirene dioxide system. No wonder, therefore, that the successful synthesis of the first member in this series (e.g. 19b) has initiated and stimulated several studies , the main objective of which was to determine whether or not thiirene dioxides should be considered to be aromatic (or pseudo-aromatic ) and/or to what extent conjugation effects, which require some sort of n-d bonding in the conjugatively unsaturated sulfones, are operative within these systems. The fact that the sulfur-oxygen bond lengths in thiirene dioxides were found to be similar to those of other 802-containing compounds, does not corroborate a Hiickel-type jr-delocalization... 

Among the olefination reactions, those of phosphonium ylides, phosphonate anions, silylmethyl anions, and sulfone anions are discussed. This chapter also includes a section on conjugate addition of carbon nucleophiles to a, (J-unsaturated carbonyl compounds. The reactions in this chapter are among the most important and general of the carbon-carbon bond-forming reactions. 

With aldehyde donors, the reactions are generally syn selective. A range of acceptors can be used, including a,p-unsaturated nitro compounds [72, 270, 274-281], a,p-unsaturated ketones [71, 282-285], vinyl phosphonates [286] and vinyl sulfones [287] etc. (Scheme 27). So far, no general anti selective... 

This works especially well when the negative charge in the intermediate Meisenheimer-like complex is stabilized, as in fluorinated a./i-unsaturated carbonyl compounds.2 74 7t) quinones8084 (e.g., 281) or vinyl sulfones.85... 

Vinyl fluorides,1 Fluoro(phenylsulfonyl)methylithium (2), obtained by reaction of 1 with BuLi in THF at — 78°, reacts with carbonyl compounds to form fluorohydrins (3), which are dehydrated to (E)-a-fluoro-a,p-unsaturated sulfones (4) in 67-92% yield with CH3S02C1 or orthophosphoric acid. Conversion of 4 into vinyl fluorides (5) is effected with aluminum amalgam (—90% yield). The vinyl fluorides are obtained as a 1 1 mixture of (E)- and (Z)-isomers. 

The 2,3-double bond in benzo[6]thiophene-1,1-dioxides undergoes addition reactions with nucleophiles in a manner comparable to that of other a,/9-unsaturated sulfones no aromatic properties are detectable in this way for the thiophene ring.718-723 For example, thiophenol and p-thiocresol give the adducts (340 R = H or Me) in the presence of base.723 However, if the aryl mercaptan and the sulfone are heated together, a radical reaction occurs to give the corresponding 2-substituted compound.723 In contrast to the behavior of aryl mercap-... 

Examples are the sulfonating of polyethylene film with chloro-sulfonic acid (60) the sulfonating of sheets of phenolformaldehyde resin (77) the treatment of a film consisting of polystyrene and polyvinylchloride with concentrated sulfuric acid (4) the sulfonating of films consisting of aliphatic vinylpolymers with chlorosulfonic acid (125) the sulfonating of copolymers of a monovinyl- and a polyvinyl compound (30). Also are used copolymers of aromatic monovinyl-compounds and linear aliphatic polyene hydrocarbons (3) copolymers of an unsaturated aromatic compound and an unsaturated aliphatic compound (76), and of reaction products of poly olefines and partially polymerized styrene (173). 

S. G. Pyne, Addition of Metalated Allylic Phosphine Oxides, Phosphonates, Sulfones, Sulfoxides and Sulfoximines to a,/3-Unsaturated Carbonyl Compounds , in Stereoselective Synthesis (Houben-Weyl) 4th ed. 1996, (G. Helmchen, R. W. Hoffmann, J. Mulzer, E. Schaumann, Eds.), 1996, Vol. E21 (Workbench Edition), 4, 2068-2086, Georg Thieme Verlag, Stuttgart. 

Carretero and co-workers reported that the a-sulfonyl radicals resulting from such radical additions to y-oxygenated-a,P-unsaturated sulfones are useful intermediates for the generation of a second carbon-carbon bond via intramolecular addition to a suitably located carbon-carbon double bond.46,47 The highly functionalized acyclic y-hydroxy vinyl sulfone 68 underwent a novel cascade process, based on two sequential radical cyclizations, affording the bicyclic compounds 69 and 70 in good yield (Scheme 18). 

The selenosulfonates (26) comprise another class of selenenyl pseudohalides. They are stable, crystalline compounds available from the reaction of selenenyl halides with sulftnate salts (Scheme 10) or more conveniently from the oxidation of either sulfonohydrazides (ArS02NHNH2) or sulftnic acids (ArS02H) with benzeneseleninic acid (27) (equations 21 and 22). Selenosulfonates add to alkenes via an electrophilic mechanism catalyzed by boron trifluoride etherate, or via a radical mechanism initiated thermally or photolytically. The two reaction modes produce complementary regioselectivity, but only the electrophilic processes are stereospecific (anti). Similar radical additions to acetylenes and allenes have been reported, with the regio- and stereochemistry as shown in Scheme 11. When these selenosulfonation reactions are used in conjunction with subsequent selenoxide eliminations or [2,3] sigmatropic rearrangements, they provide access to a variety of unsaturated sulfone products. 

The olefination based upon the reaction of benzothiazolyl- and phenyltetra-zolyl sulfones with carbonyl compounds is widely used in the target-oriented synthesis. In order to illustrate the reaction scope, yields and stereoselectivities, in this section we present selected examples of these reactions. The examples include reactions of saturated sulfones with saturated aldehydes, saturated sulfones with o, j6-unsaturated carbonyl compounds, -unsaturated sulfones with saturated aldehydes, and /l,y-imsaturated sulfones with a, -unsaturated aldehydes. The emphasis is given to recent work. A complete account of earlier applications of the modified Julia reaction has been given in the Blakemore review [98]. 

Electrolysis of benzothiete sulfone 269 yields the phenylmethanesulfinate anion (major) and the o-toluenesulfinate anion (minor).Thermolysis 618,619 gj. photolysis of thiete 1,1-dioxides proceeds via ring-opening to vinyl sulfines, for example. 288, which have been trapped by reaction with water, phenol,methanol, or norbornenes. These intermediates may recyclize to unsaturated sultines (cyclic sulfinate esters) (e.g., 289) or lose sulfur monoxide to give mainly the trans isomers of a,j3-unsaturated carbonyl compounds (e.g., 290). Mass spectra also indicate the formation of unsaturated sultines. ... 

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