Unsaturated Sulfones Research Articles

ChemInform Abstract: Further Radical‐Induced Cyclizations of Unsaturated Sulfones.

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Further radical induced cyclisations of unsaturated sulfones

Radical induced cyclisations of unsaturated sulfones by the endo-5-exo- and the exo-5-exo-ipso-modes are described. Thus the unsaturated allylic sulfones 4, 6 and 8 underwent cyclisation to the cyclopentyl sulfones 5, 7, and 9 and 10 respectively, while the unsaturated vinylic sulfones 14 and 15 were isomerised to the cyclopentylmethyl sulfones 17 and 18 respectively.

Synthetic and Mechanistic Aspects of Some Free-Radical and Electrophilic Organoselenium Reactions

Abstract Selenenic derivatives such as selenosulfonates (PhSeSO2Ar) and selenenyl sulfonates (PhSeOSO2Ar) undergo free-radical and electrophilic additions to unsaturated organic substrates, often with high regio- and stereoselectivity. These processes can be employed in tandem with selenoxide eliminations, [2,3]-sigmatropic rearrangements and various types of substitution and reduction reactions of the selenium moiety. Applications include preparations of various types of synthetically useful unsaturated sulfones and a new protocol for the synthesis of sterol side chains, such as that of the plant growth-promoter brassinolide.

2,3-Dihalo-1-(phenylsulfonyl)-1-propenes as versatile reagents for the synthesis of annulated furans and cyclopentenones

2,3-Dihalo-1-(phenysulfonyl)-1-propenes (DBP and DIP) are conveniently prepared by treating 1-(phenylsulfonyl)-1,2-propadiene with the appropriate halogen. These novel reagents undergo reaction with a variety of simple β-dicarbonyl anions to give substituted and annulated furans. When the reaction is carried out in polar solvents, 2,3,4-trisubstituted furans are formed. The reaction proceeds by an initial addition-elimination of the carbanion onto the vinyl carbon of the unsaturated sulfone which is followed by intramolecular ring closure on the enolate oxygen atom

SYNTHESIS OF SOME NOVEL α,β-ETHYLENIC SULFONES

Abstract Novel unsaturated sulfones E-alkoxy/carbamoyl benzyl styryl sulfones (VI) and E-4(N-benzylcarbamoyl)benzyl styryl sulfones (IX) have been prepared by the Knoevenagel condensation of alkoxy/ carbamoyl benzylsulfonylacetic acid (V) and 4-carboxybenzylsulfonylacetic acid (VIII) with araldehydes. The E-geometry of these compounds has been assigned based on IR and 1H NMR spectral data.

Selectivity and Mechanism of Action of Novel DNA‐Cleaving Sulfones

A simple intercalating group like a naphthyl substituent increases the ability of unsaturated sulfones such as 1 to cleave DNA, as demonstrated by compounds 2 and 3. A selective attack on the guanine residue has been proven for 1. The mechanism of action of this class of compounds involves an alkylation reaction.

Dry Reaction Under Microwave: Condensation of Sulfones with Aldehydes on KF-Alumina

Abstract Ethyl phenylsulfonylacetate(1), phenylsulfonylacetonitrile(2) and phenylsulfonylacetophenone (3) were condensated with aldehydes (a-d) into unsaturated sulfone without solvent in the presence of KF on alumina under microwave irradiation.

Mechanism of telomerization of 1,3-dienes with sulfinic acids, catalyzed by palladium complexes

The probable telomerization mechanism was studied by IR spectroscopy, according to which the reaction of 1,3-dienes with sulfinic acids proceeds through a stage of formation of S-sulfinate complexes of palladium, which bring about the formation of molecules of unsaturated sulfones.

ChemInform Abstract: A Stereocontrolled Cyclopentenone Synthesis via Cycloaddition.

AbstractThe palladium‐catalyzed methylenecyclopentanellation of the unsaturated sulfones (I) proceeds with high diastereoselectivity to give the isomers (III) as main products, the deprotected alcohols (V) of which undergo ozonolysis to give the fused cyclopentenones (VI).

A practical route to (E)-γ-hydroxy-αβ-unsaturated phenyl sulfones

Reaction of enolizable aldehydes with p-tolylsulfinylmethyl phenyl sulfone (1) in the presence of piperidine in acetonitrile gave selectively E-γ-hydroxy-αβ-unsaturated phenyl sulfones (2) in good yields. Reaction from enantiomerically pure sulfoxide 1 gave unsaturated sulfones 2 in moderate optical yields (ee= 10-50%).

ChemInform Abstract: A New Class of DNA‐Cleaving Molecules: pH‐Dependent DNA Cleavage by Propargylic and Allenic Sulfones.

AbstractA variety of 11 cyclic and acyclic unsaturated sulfones such as (VII)‐(X) are prepared as shown for (VII) or by common methods.

ChemInform Abstract: Organic Reactions without Solvent: Michael Additions on an Unsaturated Sulfone and Sulfoxide.

AbstractThe Michael type reaction of the trisubstituted CH‐acidic compounds (I) with the activated olefins (II), mediated by potash and benzyltriethylammonium chloride, is performed in the solid phase to produce the adducts (III).

3-Bromo-2-t-butylsulfonyl-1-propene.a versatile multi-coupling reagent part 1

The 3-bromo-2-t-butylsulfonyl-1-propene 3 was prepared in two steps from allyl-t-butylthioether in 70% overall yield. This reagent reacts selectively with a broad range of nucleophiles (amine, thiolate, lithium ester- and keto- enolates, magnesium, zinc and lithium organomatallics) to furnish the unsaturated sulfones of type 4 in typical yields of 80–90%. The sulfone 3 reacts also in the presence of zinc with various electrophiles (aldehydes, ketonos, nitriles and an imine) to afford the functionalized unsaturated sulfones of type 7 in good yields.

An easy synthesis of the 2-phenylsulfonyl-substituted allylic bromides and acetates and their reactivity towards nucleophiles

The reaction of phenyl vinyl sulfone with various aldehydes in the presence of a catalytic amount of DABCO furnishes in good yields teh corresponding 2-phenylsulfonyl-substituted alcohols 5a–5e which can be easily converted into their acetates 2a–2b or into their allylically rearranged bromides 3a–3d . These reagents, in turn, react with nucleophides (ketone enolates and cuprates) with an allylic rearrangement (S N2′ mechanism) to give the functionalized unsaturated sulfones 6a-g and 7a-g . A palladium catalyzed reaction allows a stero-controlled transformation of the sulfone 6b into the (Z,Z) skipped 1,4-diene 8 .

Structure of 2-(p-bromophenoxy)-N-ethyl-2-phenyl-N-(p-tolyl)ethanesulfonamide, C23H24BrNO3S

M r = 4 7 3 . 9 , triclinic, P] , a = 11.560(2), b = 10.356(1), c = 10.549(1)A, ~=90 .15 (1), f l= 111.94(1), y = 1 0 7 . 9 2 ( 1 ) °, V = 1 1 0 4 . 7 A 3, Z = 2 , Dm(flotation in benzene/carbon tetrachloride) = 1.42 (1), D x = 1.43 Mg m -3, graphite-monochromated Mo Kct, 2 = 0.7107/~, /t(Mo K~t) = 4.12 mm -1 , F(000)=488, T = 2 9 6 K, R =0.0526 for 2916 diffractometer-measured reflections (at 293 K). The compound is a racemate in which two enantiomers are related by a center of symmetry. The S-N(sp 2) and S-C(sp 3) bond lengths are 1-618 (5) and 1.779 (6)A, respectively. This investigation suggests that the reaction of aminoaryl-oxyoxosulfonium ylide and benzaldehyde involves a four-membered-ring intermediate (q-c-s-Q). Introduction. After the original work by Corey & Chaykovsky (1965), several kinds of reactions of sulfur ylides have been reported. These ylides are now used as methylene transfer'reagents (Chalkley, Snodin, Stevens & Whiting, 1970, 1978). However, no report has yet been published that sulfur ylides react with carbonyl compounds to give unsaturated sulfones via fourmembered cyclic intermediates. The authors have recently found that the reaction of aminoaryl-oxyoxosulfonium ylide (2) with benzaldehyde gave two compounds, a, fl-unsaturated sulfonamide (3) and a compound (4) which could not be identified by spectroscopic methods (Okuma, Tanaka & Ohta, 1981) (Tol is p-tolyl).

5-Endo-Trigonal ring closures of unsaturated sulfones.

The γ -functionalized unsaturated sulfones 5a-5d, 8, 11 and 15 respectively cyclize to the 5-membered heterocycles 6a-6d, 9, 14 and to the 5-membered carbocycle 16 in good yields. These ring closures are all 5-Endo-Trig processes.

3-Bromo-2-(tert-butylsulfonyl)-1-propene. A multi-coupling reagent. Part 2.

3-bromo-2-(tert-butylsulfonyl)-1-propene 1 reacts in good yields with various electrophiles (aldehydes, ketones, nitriles and alkynes) in the presence of zinc metal to give unsaturated sulfones of type 4. These compounds can further react with soft or hard nucleophiles (alkyl-, vinyl-, aryllithium compounds, a nitroparaffin or dimethylmalonate) to yield highly functionnalized sulfones of type 5 which can be readily transformed into enones or into a dienone. Thus sulfone 1 is a versatile multi-coupling reagent which is synthetically equivalent to the a 2 a 2′ synthon 8 and to the d 2 d 2′ synthons 9 and 10.

Synthesis, stereochemistry, and transformations of (E)-1,2-bis(benzenesulfonyl)ethylene cycloadducts to 2-oxa substituted 1,3-dienes

The cycloaddition of (E)-1,2-bis(benzenesulfonyl)ethylene (2) to 2-acetoxy- and 2-silyloxy-1,3-cyclodienes occurs in high yields and with high steroselectivity. Structure assignment has been based largely on 1H nmr nuclear Overhauser effect (nOe) experiments on the isolated products. The cycloadducts 4a and 4b derived from the 2-oxa substituted cyclopentadienes have been further elaborated to the parent norbornenone, to the respective unsaturated sulfones 5, and to the β-hydroxy substituted sulfone 6. The vinyl sulfones 5 have also been independently synthesized via cycloaddition of benzenesulfonyl acetylene. The sulfones obtained are potentially important starting molecules for the preparation of more complex targets.

Organic synthesis with sulfones XXXII. A convenient route to α,β -unsaturated sulfones from saturated sulfones.

α-sulfonyl litiated anions are oxidized by cupric carboxylates into β, β-unsaturated sulfones. Primary sulfones lead to pure trans-vinylic sulfones.

Synthesis of aromatic and heteroaromatic unsaturated sulfones using palladium complex catalysts

1. The nature and structure of the substituent in arylsulfinic acids slightly influence the direction of their telomerization with butadiene, and in almost all experiments this leads to a mixture of butenyl and octadienyl sulfones. 2. Low-valence palladium complexes, modified by secondary amines, nitrobenzene, or 18-dibenzo-6-crown ether, are effective catalysts of the telomerization of aromatic sulfinic acids with butadiene.