Rhenium-catalyzed regio- and stereoselective addition of two carbon units to terminal alkynes via carbon-carbon bond cleavage of β-keto sulfones

Treatment of β-keto sulfones with terminal alkynes gave unsaturated δ-keto sulfones in good to excellent yields under rhenium catalysis. In this reaction, the insertion of the alkynes into the nonstrained carbon-carbon single bond between the α- and β-positions of the β-keto sulfones proceeded smoothly, and (Z)-isomers were produced with high regio- and stereoselectivities.     

Electrochemical Fluorination of Unsaturated Sulfides and Sulfones

Electrochemical fluorination of some unsaturated sulfides and sulfones and their reactions with anhydrous HF were studied.     

Enantioselective synthesis of chiral sulfones by ir-catalyzed asymmetric hydrogenation: a facile approach to the preparation of chiral allylic and homoallylic compounds

A highly efficient and enantioselective Ir-catalyzed hydrogenation of unsaturated sulfones was developed. Chiral cyclic and acyclic sulfones were produced in excellent enantioselectivities (up to 98% ee). Coupled with the Ramberg-B?cklund rearrangement, this reaction offers a novel route to chiral allylic and homoallylic compounds in excellent enantioselectivities (up to 97% ee) and high yields (up to 94%).     

Synthesis of substituted quinolines using the dianion addition of N-Boc-anilines and alpha-tolylsulfonyl-alpha,beta-unsaturated ketones

A short and versatile synthesis of substituted quinolines is provided. Alkylation of sodium tolylsulfinate with bromomethyl- or chloromethyl ketones generates beta-keto sulfones. Knoevenagel condensation of the beta-keto sulfones with an aldehyde provides alpha-tolylsulfonyl-alpha,beta-unsaturated ketones. Michael addition of the dianion of N-Boc-anilines in the presence of CuCN and LiCl with the unsaturated ketone generates a 1,4-adduct, which after deprotection of the Boc group and thermal elimination of the tolyl sulfone provides the quinoline.     

BCl3‐Mediated Ene Reaction of Sulfur Dioxide and Unfunctionalized Alkenes

The first ene reactions of SO₂ and unfunctionalized alkenes are reported. Calculations suggest that the endergonic ene reactions of SO₂ with alkenes can be used to generate β,γ‐unsaturated sulfinyl and sulfonyl compounds. Indeed, in the presence of one equivalent of BCl₃, the unstable sulfinic acid form stable sulfinic acid?BCl₃ complexes that can be reacted in situ with NCS to generate corresponding sulfonyl chlorides, or with a base to generate corresponding sulfinates. The latter can be reacted with electrophiles to generate sulfones, or with silyl chloride to form β,γ‐unsaturated silyl sulfinates. The sulfinic acid?BCl₃ complexes can be reacted with ethers that act as oxygen nucleophiles to produce corresponding sulfinic esters. Thus one‐pot, three‐component synthesis of β,γ‐unsaturated sulfonamides, sulfinyl esters and sulfones have been developed starting from alkenes and sulfur dioxide (reagent and solvent).     

Addition to electron deficient olefins of alpha-oxy carbon- centered radicals, generated from cyclic ethers and acetals by the reaction with alkylperoxy- lambda(3)-iodane

Thermal decomposition of 1-tert-butylperoxy-1,2-benziodoxol-3(1H)-one in cyclic ethers and acetals at 50 degrees C generates alpha-oxy carbon-centered radicals, which undergo an addition reaction with vinyl sulfones and unsaturated esters.     

Syntheses a l'aide de sulfones (xxxvii): Synthese de trois pheromones a une double liaison z : z, 8-dda ; z, 9-dda ; z. 9-tda

The title compounds Z,8-dodecen-1yl acetate, Z,9-dodecen-1yl acetate and Z,9-tetradecen-1yl-acetate) have been synthesized in three efficient steps : the reaction mixture from metalated w-hydroxy sulfones and appropriate aldehydes was quenched with acetic anhydride yielding a diastereoisomeric mixture of β-acetoxy sulfones. Convergent elimination with powdered sodium hydroxide led to the E vinylic sulfone. Stereospecific hydrogenolysis of the sulfonyl group was carried out with sodium dithionite leading to the unsaturated alcohol (99% Z).     

An Improved Synthesis of Vinyl- and β-Iodovinyl Sulfones by a Molecular Iodine-Mediated One-Pot Iodosulfonation-Dehydroiodination Reaction

An improved one-pot method to synthesize vinyl sulfones from unsaturated systems by using molecular iodine/sodium arenesulfinate/sodium acetate as reagents was described. Vinyl sulfones derived from styrene derivatives were generally obtained in good to excellent yields except for those bearing strong electron releasing substituent. Aliphatic alkenes and activated alkenes gave the corresponding vinyl sulfone products in moderate to good yields. Arylacetylenes yielded the respective β-iodovinyl sulfones in good yields while low yield was observed with aliphatic terminal alkyne. The potentials of the method entail simplicity, short reaction time, non-anhydrous reaction conditions, employing inexpensive, non-metallic reagent and integrating two reactions that are commonly accomplished separately into a single operation.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Catalytic enantioselective tandem carbonyl ylide formation—intramolecular cycloaddition with unsaturated α-diazo-β,ε-diketo sulfones

The synthesis and 1,3-dipolar cycloaddition reactions of unsaturated α-diazo-β,ε-diketo sulfones 7 using chiral rhodium catalysts (up to 71.5:28.5 er) are described.     

A Stereoselective Cathodic Coupling of Aryl Styryl Sulfones

Abstract

The cathodic coupling of unsaturated sulfones (title compounds) performed in aprotic media in the presence of lithium salts as electrolyte affords d,l dimers almost exclusively.     

固载离子液体刷/过氧磷钨酸盐催化剂催化H2O2选择性氧化硫醚

以二氧化硅为载体,合成了一种新型的双层离子液体刷固载过氧磷钨酸盐催化剂.采用元素分析、IR和SEM-EDAX等手段对催化剂进行了表征.室温下,考察了该催化剂催化30％(质量分数)H2O2溶液选择性氧化硫醚为亚砜或砜的催化性能.结果表明,该催化剂具有很高的催化活性和选择性.采用1.1倍H2O2时,反应选择性地生成亚砜,仅...     

Titanocene(II)-promoted stereoselective alkenylation utilizing (Z)-alkenyl sulfones

The stereoselective alkenylation of unsaturated compounds by means of a (Z)-alkenyl sulfone-titanocene(II) system is described. Treatment of alkynes and (Z)-alkenyl methyl sulfones with the titanocene(II) reagent Cp2Ti[P(OEt)3]2 produced conjugated dienes. This alkenylation system is also applicable to polar C=O bonds; the simple mixing of carbonyl compounds, (Z)-alkenyl methyl sulfones, and the titanocene(II) reagent formed allylic alcohols. The advantages of alkenylation are that it requires no prepreparation of the alkenylmetal reagent and that it proceeds with complete stereoselectivity.     

Conjugate additions of o-iodoanilines and methyl anthranilates to acetylenic sulfones. A new route to quinolones including first syntheses of two alkaloids from the medicinal herb Ruta chalepensis

A novel synthesis of 2-substituted 4-quinolones was developed on the basis of the conjugate additions of appropriately ortho-substituted anilines to acetylenic sulfones followed by intramolecular acylation of the corresponding sulfone-stabilized anions. Conjugate additions of variously substituted anilines to alkyl-substituted acetylenic sulfones generally proceeded slowly and in poor yield, especially when the aniline contained an electron-withdrawing substituent such as an ester group. In some cases, the reactions were enhanced by the presence of DMAP and the use of an excess of the sulfone in aqueous DMF. N-Formylanilines proved superior to free anilines. The products were either vinyl or allyl sulfones, depending on the conditions and the structure of the reactants. The acetylenic sulfone exists in equilibrium with its allenic and propargylic isomers under base-catalyzed conditions. Therefore, any of the three unsaturated sulfones can serve as the starting material for the conjugate additions. o-Iodoanilines proved superior to methyl anthranilate derivatives and underwent conjugate additions smoothly. The products were subjected to palladium-catalyzed carbonylation in methanol, and the resulting methyl esters were cyclized by treatment with strong bases such as LiHMDS or LiTMP, followed by reductive desulfonylation with aluminum amalgam. The resulting 2-substituted 4-quinolones included the naturally occurring medicinal compounds 1 and 2 and the O-methyl derivative 3.     

Cycloadditions dipolaires-1,3 sur les F-alkyl sulfones α-β insaturees

Cycloadditions of diazomethane and N-methyl nitrone with α,β, unsaturated F-hexyl sulfones substituted on C_β by an aromatic group were investigated. Compounds obtained depend on the nature of the aromatic group, and a mechanism is proposed for their formation.     

Cyclic sulfoxides. I. dihydrothiophene 1-oxides

Although there have been extensive investigations on cyclic sulfones, especially the unsaturated, 5-membered ring compounds (3), cyclic sulfoxides have received considerably less attention. In this report, we wish to present a synthesis of the previously unknown dihydrothiophene 1-oxide isomers and, also, some preliminary results regarding their chemical reactivity (4).     

Asymmetric Claisen Rearrangements on Chiral Vinyl Sulfoxides

Highly diastereoselective Claisen rearrangements of acyclic allyl vinyl ethers bearing a chiral sulfoxide at C‐5 provide γ‐δ‐unsaturated aldehydes or ketones with up to two consecutive asymmetric centers in the molecule whilst preserving a useful vinyl sulfoxide. The reactivity of related vinyl sulfides and sulfones has also been examined in this work.     

Synthesis and evaluation of 3-(carboxymethylidene)- and 3-(carboxymethyl)penicillinates as inhibitors of beta-lactamase

Penicillin-resistant bacteria can often be treated through the co-administration of an antibiotic and a beta-lactamase inhibitor. Current inhibitors target only class A beta-lactamases. We report two new series of C3-modified penicillin sulfones, having either a simple methylene group (i.e., a homologue) or exocyclic unsaturation between the thiazolidine ring and the C3 carboxylate. The homologue has 10-fold better activity against a class C beta-lactamase than does sulbactam itself. By contrast, the exocyclic C3 unsaturated compounds are less active.     

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.     

Rhodium‐Catalyzed Regioselective C7‐Functionalization of N‐Pivaloylindoles

An efficient rhodium‐catalyzed method for direct C? H functionalization at the C7 position of a wide range of indoles has been developed. Good to excellent yields of alkenylation products were observed with acrylates, styrenes, and vinyl phenyl sulfones, whereas the saturated alkylation products were obtained in good yield with α,β‐unsaturated ketones. Both the N‐pivaloyl directing group and the rhodium catalyst proved to be crucial for high regioselectivity and conversion.     

Dipole moments of sulfones of acetylene series

Conclusions The dipole moments of a number of acetylenic sulfones of general formula RSO₂CCH were measured. Considerations were expressed regarding the character of the interaction of the sulfonyl group with unsaturated radicals.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 462–464, February, 1973.