Regio- and stereospecific synthesis of vinyl halides via carbozincation of acetylenic sulfones followed by halogenation

Polysubstituted vinyl halides can be constructed regio- and stereospecifically by treatment of acetylenic sulfones with organozinc reagents in tetrahydrofuran followed by halogenation.     

Regioselective synthesis of highly-substituted biaryls by reaction of vinyl malononitriles with acetylenic esters

The one-pot procedure for synthesis of highly-substituted biaryl derivatives has been described via cyclocondensation reaction between vinyl malononitriles and acetylenic esters. A series of complex biaryls containing one-donor and three-acceptor moieties was obtained with good yields.     

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.     

Regio- and stereoselective synthesis of tetrasubstituted allylic alcohols by three-component reaction of acetylenic sulfone, dialkylzinc, and aldehyde

(Z)-Tetrasubstituted allylic alcohols bearing sulfonyl group were synthesized regio- and stereoselectively by alkylzincation of acetylenic sulfone followed by addition to aldehyde.     

Regio- and stereoselective synthesis of highly functionalized vinyl ethers via coiodination of acetylenic ketones

A Cu(OTf)₂-catalyzed highly regio- and stereoselective coiodination of acetylenic ketones was reported, providing a mild and convenient method for the synthesis of (Z)-β-carbonyl-β-iodoenol ethers in good yields.     

Highly efficient, catalytic bis addition reactions of allyl phenyl sulfone to vinyl sulfones

Highly efficient, electrocatalytic additions of allyl phenyl sulfone to a variety of vinyl sulfones have been accomplished. The additions are catalyzed by electrogenerated bases derived from the reactant itself, and furnish 90-94% yields of highly polar molecules in which 1 mol of allyl phenyl sulfone has added consecutively, selectively, and in a linear addition mode to 2 mol of the vinyl sulfone. Essentially no products are observed which incorporate other than 2 mol of the vinyl sulfone. An addition to a difunctional alkene, divinylsulfone, yields a novel cyclization product, albeit in more moderate yield (41%). The use of tetraalkylammonium salts, as opposed to lithium salts, as electrolytes has been found to provide electrogenerated bases of especially high reactivity.     

Fragmentation of carbohydrate anomeric alkoxyl radicals. Synthesis of highly functionalized chiral vinyl sulfones

The reaction of derivatives of 3-acetyl-d-glucal, 3-acetyl-l-rhamnal, 3-acetyl-d-galactal, and 3-acetyl-d-lactal with sodium benzenesulfinate in acid medium catalyzed by HgSO₄ afforded diastereoisomeric mixtures of the corresponding 2,3-dideoxy-3-(phenylsulfonyl)-hexopyranoses through a Ferrier rearrangement. The anomeric alkoxyl radical fragmentation of these γ-hydroxy sulfones using the system (diacetoxyiodo)benzene and iodine gave vinyl sulfones with structures of 1,2-dideoxy-4-O-formyl-2-(phenylsulfonyl)-pent-1-enitol and configurations d-erythro, l-erythro, and d-threo at the two stereogenic centers.     

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.     

cis-Carbocuperation of acetylenic sulfoxides and corresponding applications in the regio- and stereoselective synthesis of polysubstituted vinyl sulfoxides

cis-Carbocuperation reaction of monoorganocopper reagent with acetylenic sulfoxides, followed by electrophilic reaction with a variety of electrophiles, provided a regio- and stereoselective method to prepare the versatile polysubstituted vinyl sulfoxides. Sonogashira cross-coupling reaction of the obtained α-iodovinyl sulfoxides with terminal acetylenes was also investigated to afford the versatile conjugate sulfinyl enynes.     

Convenient synthesis of α,β-unsaturated sulfones via a Mizoroki-Heck reaction of arylboronic acids with phenyl vinyl sulfones

Palladium acetate catalyzed Mizoroki-Heck reaction of arylboronic acids with phenyl vinyl sulfones afford α,β-unsaturated sulfones in good yields.     

CuI-catalyzed tandem carbomagnesiation/carbonyl addition of Grignard reagents with acetylenic ketones: Convenient access to tetrasubstituted allylic alcohols

Highly functionalized tetrasubstituted allylic alcohols were prepared conveniently by CuI-catalyzed tandem carbomagnesiation/carbonyl addition of Grignard reagents with acetylenic ketones. The obtained allylic alcohols can be further transformed to polysubstituted indenes by intramolecular cyclization.     

A Stereoselective Synthesis of Substituted Allyl Alcohol by Threecomponent Rection of Acetylenic Sulfone, Phenylselenomagnesium Bromide and Ketones

Phenylseleno and sulfonyl substituted allyl alcohols were synthesized stereoselectively by the three-componem reaction of acetylenic sulfone, phenylselenomagnesium bromide and ketones in one-pot.     

Cross-metathesis reaction of vinyl sulfones and sulfoxides

Cross-metathesis reactions of α,β-unsaturated sulfones and sulfoxides in the presence of molybdenum and ruthenium pre-catalysts were tested. A selective metahesis reaction was achieved between functionalized terminal olefins and vinyl sulfones by using the ‘second generation’ ruthenium catalysts 1c-h while the highly active Schrock catalyst 1b was found to be functional group incompatible with vinyl sulfones. The cross-metathesis products were isolated in good yields with an excellent (E)-selectivity. Both the molybdenum and ruthenium-based complexes were, however, incompatible with α,β- and β,γ-unsaturated sulfoxides.     

Three types of products by carbon nucleophiles toward methoxyphenylacetylenic sulfones

Methoxy-arylacetylenic sulfones were examined to react with various carbanion nucleophiles to result in the three types of products; thus, (i) nucleophiles (MeLi·LiBr, Vinyl MgBr, LiCH₂CN) showed the α-addition, however, (ii) Li-CC-TMS afforded β-addition (conjugate addition) products. The (iii) displacement reaction through α-addition/isomerization/trans-elimination was enhanced by the presence of ortho-methoxy group at high temperature. The heteroatom nucleophiles (nitrogen, oxygen or sulfur atom) in a protic solvent provided only conjugate addition products as reported.     

Cyclo- and carbomagnesiation of 1,2-dienes catalyzed by Zr complexes

Cyclo- and carbomagnesiation of 1,2-dienes with EtMgR′ (R′=Et, Br) in the presence of Cp₂ZrCl₂ catalyst lead to alkylidenemagnesiocyclopentanes. Deuterolysis provides insights into the reaction pathways.     

Vinyl sulfone- and vinyl sulfoxide-modified tetrahydrofurans: a preliminary account of the enantiomeric synthesis of and diastereoselectivity of addition to new classes of Michael acceptors

Enantiomerically pure 2-hydroxymethylene substituted-2,5-dihydro-3-(arylsulfonyl)- and 2-hydroxymethylene substituted-2,5-dihydro-3-(arylsulfinyl)-furans have been prepared from easily accessible carbohydrate derivatives for the first time. The strategy for accessing both these sulfones and sulfoxides is more efficient than the methods reported so far for the synthesis of this type of compounds. Hydroxymethylene group is sufficient to impose diastereoselectivity on the addition of a wide range of nucleophiles to vinyl sulfone-modified tetrahydrofurans. The benzyl protected hydroxymethylene group also suppresses the influence of chirally pure sulfoxides as two diastereomeric vinyl sulfoxide-modified tetrahydrofurans afforded the Michael adducts with same configurations at C-3 and C-4; this has been established by oxidizing the adducts, which were found to be identical to the products obtained by adding the same nucleophiles to the corresponding vinyl sulfones. These highly reactive Michael acceptors may be considered as a new addition to the arsenals of synthetic chemists interested in the functionalization of tetrahydrofurans.     

Stereoselective Synthesis of Allylic Amines by One-Pot Tandem Reaction of Acetylenic Sulfone,Grignard Reagent,and N-Tosylimine

Polysubstituted allylic amines were regio- and stereoselectively synthesized by a one-pot tandem reaction of Cu(I)-catalyzed carbomagnesiation of acetylenic sulfones and its further reaction with N-tosylimine.     

Stereoselective synthesis of allylic sulfones via the oxonia-Cope rearrangement of homoallylic alcohols containing a homoallylic sulfone moiety

The homoallylic alcohols 3 that can be prepared by the indium-mediated addition of haloallylic sulfones 1 to aldehydes 2 undergo the oxonia-Cope rearrangement with aldehydes 2 to give rise to the allylic sulfones 4 containing a conjugated diene moiety in a highly stereoselective manner. Electron-rich aldehydes preferentially participate in this oxonia-Cope rearrangement with the homoallylic alcohols 3. Excellent correlations of the stereochemistry (anti-3 to trans-allylic sulfone 4 and syn-3 to cis-allylic sulfone 4) have been observed in the oxonia-Cope rearrangement.     

Catalyzed double Michael addition of anilines to vinyl sulfone

Substituted anilines and vinyl sulfone undergo a facile double Michael addition to form substituted phenylthiomorpholine dioxide, catalyzed with AlCl₃ or H₃PO₄. Scope and conditions were explored.