A simple synthesis of azabicyclo[1.1.0]butane sulfones and sulfoxides

Azirines react with carbanions derived from α-chloro sulfones and sulfoxides, under mild conditions, to form functionalized azabicyclo[1.1.0]butanes.     

Organic synthesis with sulfones XXXVIII: On the mechanism of the stereospecific hydrogenolysis of vinylic sulfones by sodium dithionite

The stereospecific hydrogenolysis of vinylic sulfones by sodium dithionite in a protic medium proceeds by addition of HSO₂ to give an intermediate which could be isolated after alkylation in situ to a 1,2-bissulfone. The mechanism is therefore of the β-addition-elimination type. In the case of E-2-benzenesulfonyl-2-butene and ethyl iodide a single crystalline diastereoisomer was obtained and shown to have the threo configuration by X-ray crystallography. The addition step follows the syn and the elimination step the anti stereochemistry, thus accounting for the overall retention of configuration observed.     

高效薄层色谱扫描法测定烟草中β-胡萝卜素

摘要：建立了测定烟草中β-胡萝卜素的高效薄层色谱扫描方法,以V（苯）:V（丙酮）=4:4为展开剂,检测波长450nm,线性范围50ng～0.5μg,最低检测限20ng。方法简便、灵敏、快速、重现性好。     

One-pot synthesis of aryl biaryl sulfones

Synthesis of aryl biaryl sulfones 3 with good yields is described. The one-pot efficient synthetic route is carried by the NaH-mediated tandem [C3+C3] annulations of cinnamaldehydes 1 and propargylic sulfones 2 under the boiling THF conditions.     

Regiospecificity in the synthesis of diaryl sulfones

The addition of arylsulfinic acids to 2-methyl-1,4-benzoquinone provides high yields of sulfones in a wide variety of solvents. The distribution of isomeric products obtained is strongly influenced by either (1) the acidity of aqueous solvents or (2) the water content of alcohol solvents. The distribution of isomeric products does not change in the various anhydrous, aprotic solvents examined.     

Mild convenient synthesis of α-methylene sulfones

Reaction of paraformaldehyde with α-trifyl-sulfones and potassium carbonate at room temperature affords vinyl sulfones in good yield under mild conditions, with loss of triflate anion.     

Enantioselective synthesis of chiral sulfones by Rh-catalyzed asymmetric addition of boronic acids to alpha,beta-unsaturated 2-pyridyl sulfones

A general and efficient method for the rhodium-catalyzed enantioselective catalytic conjugate addition of organoboronic acids to alpha,beta-unsaturated sulfones is described. The success of the process relies on the use of alpha,beta-unsaturated 2-pyridyl sulfones as key metal-coordinating substrates; typical sulfones such as vinyl phenyl sulfones are inert under the reaction conditions. Among a variety of chiral ligands, Chiraphos provided the best asymmetric induction. This rhodium [Rh(acac)(C2H4)2]/Chiraphos catalyst system has a broad scope, being applicable to the addition of both aryl and alkenyl boronic acids to cis and trans alpha,beta-unsaturated 2-pyridyl sulfones. In most cases, especially in the addition of aryl boronic acids, the reactions take place cleanly and with high enantioselectivity, affording chiral beta-substituted 2-pyridyl sulfones in good yields and enantioselectivities (70-92% ee). The sense and magnitude of this enantioselectivity have been studied by DFT theoretical calculations of the aryl-rhodium insertion step. These calculations strongly support the formation of a five-membered pyridyl-rhodium chelated species as the most stable complex after the insertion into the C=C bond. These highly enantioenriched chiral sulfones are very appealing building blocks in enantioselective synthesis. For instance, the straightforward elimination of the 2-pyridylsulfonyl group by either Julia-Kociensky olefination or alkylation/desulfonylation sequences provides a variety of functionalized chiral compounds, such as allylic substituted alkenes or beta-substituted ketones and esters.     

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.     

Regioselective synthesis of allylic sulfones by palladium-catalyzed denitro-sulfonylation of allylic nitro compounds

Allylic nitro compounds undergo denitro-sulfonylation catalyzed by Pd(PPh₃)₄ or Pd(PPh₃)₄ +NaNO₂ with PhSO₂Na·2H₂O to afford allylic sulfones regioselectively.     

Efficient conversion of sulfones into beta-keto sulfones by N-acylbenzotriazoles

Acyclic sulfones 4a-f and alicyclic sulfone 7 react with readily available N-acylbenzotriazoles 3a-g (derived from aliphatic, aromatic, and heteroaromatic carboxylic acids) to provide the corresponding beta-keto sulfones 5a-n and 8a-c, respectively, in good to excellent yields.     

Chemistry of sulfones: synthesis of a new chiral nucleophilic catalyst

A chiral pyrrolidinopyridine was synthesized by using Buchwald methodology. The sulfone was used to add a benzyl group, which positioned a phenyl near the reacting position.     

Vinyl sulfones in solid-phase synthesis: preparation of 4,5,6,7-tetrahydroisoindole derivatives

The preparation of functionalized 4,5,6,7-tetrahydroisoindole via a traceless solid-phase sulfone linker strategy is described. Thermolytic extrusion of SO(2) from polymer-bound 3-(phenylsulfonyl)-3-sulfolene (7) generated polymer-bound 2-(phenylsulfonyl)-1,3-butadiene (9) in situ which underwent Diels--Alder cycloaddition with various dienophiles to furnish vinyl sulfone resins 10-14. To complete a traceless linker cleavage strategy, (p-tolysulfonyl)methyl isocyanide or ethyl isocyanoacetate was employed to react with the vinyl sulfone moiety to liberate functionalized 4,5,6,7-tetrahydroisoindole products from the resin. Using this chemistry, nine tetrahydroisoindole derivatives (6, 15-22) were prepared in 32-41% overall yields from polystyrene/divinylbenzene sulfinate 1.     

An efficient Cu-catalyzed microwave-assisted synthesis of diaryl sulfones

An efficient and microwave-assisted simple protocol for the synthesis of symmetrical/asymmetrical diaryl sulfones through the Cu(II)-catalyzed reaction of sodium salt of sulfinic acid with aryl boronic acid has been described. Various diaryl sulfones have been synthesized in very short reaction times with moderate to very good yields. Additionally, the method is also useful for the synthesis of aryl vinyl sulfones.     

New synthesis of allylidenecyclobutanes by the reaction of cyclobutylmagnesium carbenoids with vinyl sulfones

The reaction of cyclobutylmagnesium carbenoids, which were generated from 1-chlorocyclobutyl p-tolyl sulfoxides with EtMgCl via the sulfoxide-magnesium exchange reaction at low temperature, with carbanions derived from vinyl sulfones with n-BuLi or LDA resulted in the formation of allylidenecyclobutanes in moderate to good yields. The actual reactive species of the sulfones in this reaction were proved to be the lithium α-sulfonyl carbanion of allyl sulfones derived from the vinyl sulfones by double bond migration with the bases used. Mono- and di-substituted allylidenecyclobutanes can be obtained by using a variety of vinyl sulfones.     

A general route to mono- and disubstituted divinyl sulfones: acyclic Michael acceptors for the synthesis of polyfunctionalized cyclic sulfones

Nucleophilic C-S bond formation using easily available β-hydroxysulfonate derivatives allowed direct access to new mono- and disubstituted divinyl sulfones. Our strategy uses thioethanol (HSCH(2)CH(2)OH) and its analogues such as HSCH(2)CH(Y)OH generated in situ. The strategy also allows the synthesis of modified divinyl sulfones attached to chiral appendages like carbohydrates. Bis-heteronucleophilic Michael addition reactions with 1 equiv of a primary amine afforded new generations of S,S-dioxothiomorpholine derivatives known for their therapeutic applications. Further synthetic manipulations of some of these cyclic compounds led to the synthesis of novel bicyclic derivatives.     

High-yield synthesis of fluorinated benzothiazolyl sulfones: general synthons for fluoro-julia olefinations

[reaction: see text] General, high-yield tandem electrophilic fluorination and modified Julia olefination for the synthesis of fluoro olefins is reported. A series of alpha-fluoro 1,3-benzothiazol-2-yl sulfone-based synthons were synthesized via deprotonation-fluorination. Of critical importance for high-yield fluorinations were heterogeneous reaction conditions, as under homogeneous conditions only starting sulfones were recovered. The alpha-fluoro 1,3-benzothiazol-2-yl sulfones so obtained were subjected to condensations with a variety of aldehydes and ketones to afford high yields of regiospecifically fluorinated olefins.     

Microwave-assisted synthesis of diaryl or aryl-alkyl sulfones without catalyst

The microwave-assisted coupling reaction of electrondeficient aryl halides with sulfmic acid salts through SNAr-based addition reactions within 5-30 min. No catalysts were required under our conditions.     

Regio‐ and stereospecific synthesis of polysubstituted alkenes by carbozincation of acetylenic sulfones

Tri‐ or tetrasubstituted alkenes with various substituents can be constructed regio‐ and stereospecifically by treatment of acetylenic sulfones with organozinc reagents in tetrahydrofuran followed by hydrolysis or coupling with halohydrocarbon. Copyright © 2009 John Wiley & Sons, Ltd.     

Enantiodivergent,catalytic asymmetric synthesis of gamma-amino vinyl sulfones

A set of diversely substituted N-Boc-gamma-amino vinyl sulfones has been prepared by a four-step procedure from readily available, highly enantiopure anti-N-Boc-3-amino-1,2-alkanediols. This new route, which does not depend on the accessibility of alpha-amino acids as starting materials, is noteworthy for its efficiency, for its generality, and for the fact that both enantiomers of a given gamma-amino vinyl sulfone can be obtained with equal ease.