- Controllable Activation of β-Alkyl Nitroalkenes: Regioselective Synthesis of Allyl and Vinyl Sulfones
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The regiospecific radical reactions of β-alkyl nitroalkenes with sulfonyl hydrazides depended to a great extent on the choice of a solvent and catalyst. In the presence of dimethylformamide (DMF), β-alkyl nitroalkenes more likely converted into electron-rich allyl nitro compounds, which reacted with sulfonyl hydrazides to afford allyl sulfones with high regioselectivity. While in acetonitrile (CH3CN), vinyl sulfones were obtained directly via sulfonation of electron-deficient β-alkyl nitroalkenes. The mechanism investigation revealed that the regioselectivity was controlled by the equilibrium of β-alkyl nitroalkenes and allyl nitro compounds.
- Wang, Ye,Xiong, Guowei,Zhang, Chuanxin,Chen, Yunfeng
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p. 4018 - 4026
(2021/03/01)
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- Copper-Photocatalyzed Contra-Thermodynamic Isomerization of Polarized Alkenes
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The contra-thermodynamic isomerization of α- and β-substituted cinnamate derivatives catalyzed by the Cu(OAc)2/rac-BINAP complex under blue light irradiation is reported. The use of an oxazolidinone template, which favored the complexation of the copper catalyst to the substrate, allowed the E → Z isomerization of the catalytically formed chromophore under simple and robust reaction conditions in good to excellent ratios. The mechanism of this process based on the transient formation of a chromophore was also studied.
- Bouillon, Jean-Philippe,Brégent, Thibaud,Poisson, Thomas
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supporting information
p. 7688 - 7693
(2020/10/09)
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- N,N′-Disulfonylhydrazines: New sulfonylating reagents for highly efficient synthesis of (E)-vinyl sulfones at room temperature
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N,N′-Disulfonylhydrazines have been proven to be the most reactive precursors of sulfonyl radicals in all types of sulfonyl substituted hydrazines as early as a half century ago. But such function has not been applied in organic synthesis except the formation of disulfones by self-dimerization of sulfonyl radicals. In this article, they were introduced as new sulfonylating reagents and their combinations with NIS and Et3N were established as excellent iodosulfonylating reagents for alkenes. Finally, a highly efficient method for the synthesis of (E)-vinyl sulfones was developed by mixing an alkene, a N,N′-disulfonylhydrazine, NIS and Et3N in THF at room temperature for 5 min.
- Hu, Yuefei,Luo, Dongping,Min, Lin,Shan, Lidong,Wang, Xinyan,Zheng, Weiping
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- Highly Efficient Enantioselective Synthesis of Chiral Sulfones by Rh-Catalyzed Asymmetric Hydrogenation
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A highly efficient and enantioselective Rh-(R,R)-f-spiroPhos complex catalyzed hydrogenation of a series of unsaturated sulfones has been developed. With Rh-(R,R)-f-spiroPhos catalyst under mild conditions, not only the asymmetric hydrogenation of both the 3,3-diaryl and exocyclic α,β-unsaturated sulfones was first realized with up to 99.9% ee but also 3-alkyl-3-aryl and benzo[b]thiophene-1,1-dioxides were successfully hydrogenated to the corresponding chiral sulfones with excellent enantioselectivities (up to 99.4% ee) regardless of the steric hindrance, electronic property, and geometry of the substrates. Moreover, this reaction offers a route to (S)-(+)-ar-turmerone as a spice flavor, which is an important synthetic intermediate of pharmaceuticals.
- Yan, Qiaozhi,Xiao, Guiying,Wang, Ying,Zi, Guofu,Zhang, Zhanbin,Hou, Guohua
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p. 1749 - 1756
(2019/01/25)
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- Visible Light-Mediated Metal-Free Synthesis of Vinyl Sulfones from Aryl Sulfinates
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Visible light and eosin Y catalyze the synthesis of vinyl sulfones from aryl sulfinates and alkenes by a photoredox process. The reaction scope is broad in aryl sulfinates and alkenes and the general and simple procedure provides a metal-free alternative for the synthesis of synthetically valuable vinyl sulfones.
- Meyer, Andreas Uwe,J?ger, Stefanie,Prasad Hari, Durga,K?nig, Burkhard
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p. 2050 - 2054
(2015/06/23)
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- PhI(OAc)2 mediated decarboxylative sulfonylation of β-aryl-α,β-unsaturated carboxylic acids: A synthesis of (E)-vinyl sulfones
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A highly efficient metal-free decarboxylative sulfonylation protocol for the preparation of (E)-vinyl sulfones from of β-aryl-α,β-unsaturated carboxylic acids using sodium sulfinates and (diacetoxyiodo)benzene (PhI(OAc)2) was developed. This strategy offers a simple and expedient synthesis of (E)-vinyl sulfones bearing a wide variety of functional groups. A radical-based pathway has been proposed for this decarboxylative sulfonylation reaction.
- Katrun, Praewpan,Hlekhlai, Sornsiri,Meesin, Jatuporn,Pohmakotr, Manat,Reutrakul, Vichai,Jaipetch, Thaworn,Soorukram, Darunee,Kuhakarn, Chutima
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supporting information
p. 4785 - 4794
(2015/04/27)
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- An enantioselective approach to the preparation of chiral sulfones by ir-catalyzed asymmetric hydrogenation
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Several chiral sulfonyl compounds were prepared using the iridium catalyzed asymmetric hydrogenation reaction. Vinylic, allylic and homoallylic sulfone substitutions were investigated, and high enantioselectivity is maintained regardless of the location of the olefin with respect to the sulfone. Impressive stereoselectivity was obtained for dialkyl substitutions, which typically are challenging substrates in the hydrogenation. As expected, the more bulky Z-substrates were hydrogenated slower than the corresponding E isomers, and in slightly lower enantioselectivity.
- Peters, Byron K.,Zhou, Taigang,Rujirawanich, Janjira,Cadu, Alban,Singh, Thishana,Rabten, Wangchuk,Kerdphon, Sutthichat,Andersson, Pher G.
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p. 16557 - 16562
(2015/01/09)
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- Photoredox α-vinylation of α-amino acids and N -aryl amines
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A new coupling protocol has been developed that allows the union of vinyl sulfones with photoredox-generated α-amino radicals to provide allylic amines of broad diversity. Direct C-H vinylations of N-aryl tertiary amines, as well as decarboxylative vinylations of N-Boc α-amino acids, proceed in high yield and with excellent olefin geometry control. The utility of this new allyl amine forming reaction has been demonstrated via the syntheses of several natural products and a number of established pharmacophores.
- Noble, Adam,MacMillan, David W. C.
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supporting information
p. 11602 - 11605
(2014/11/08)
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- Catalytic enantioselective reduction of β,β-disubstituted vinyl phenyl sulfones by using bisphosphine monoxide ligands
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(Chemical Equation Presented) Synthesis of chiral sulfones: A copper-phosphine complex efficiently provided optically active alkyl phenyl sulfones by hydrosilylation at room temperature. The reduction of β,β-disubstituted vinyl sulfones in the presence of the Me-DuPhos monoxide ligand lead to excellent enantiomeric excesses and high yields (see scheme). The prepared chiral sulfones were desulfonylated and subjected to Julia olefination conditions.
- Desrosiers, Jean-Nicolas,Charette, Andre B.
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p. 5955 - 5957
(2008/09/17)
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- Highly regio- and stereoselective palladium(0)-catalyzed addition of organoboronic acids with 1,2-allenic sulfones, sulfoxides, or alkyl- or aryl-substituted allenes in the presence of acetic acid: An efficient synthesis of E-alkenes
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Two sets of reaction conditions were established to enable the palladium(0)-catalyzed addition of organoboronic acids with 1,2-allenic sulfones, sulfoxides, or alkyl- or aryl-substituted allenes in the presence of acetic acid. This reaction provides a new
- Guo, Hao,Ma, Shengming
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p. 2731 - 2745
(2008/03/13)
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- Catalytic asymmetric conjugate reduction of β,β-disubstituted α,β-unsaturated sulfones
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(Chemical Equation Presented) Access to a chiral sulfone: Asymmetric conjugate reduction of β,β-disubstituted α,β-unsaturated 2-pyridylsulfones with silanes under CuI/binap catalysis provides chiral sulfones with excellent chemical yields and e
- Llamas, Tomas,Arrayas, Ramon Gomez,Carretero, Juan C.
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p. 3329 - 3332
(2008/03/12)
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- Palladium-catalyzed cascade reaction of α,β-unsaturated sulfones with aryl iodides
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Unlike traditionally used acyclic 1,2-disubstituted alkenes, the reaction of α,β-unsaturated phenyl sulfones with aryl iodides under Heck reaction conditions (Pd(OAc)2 as catalyst, Ag2-CO3 as base in DMF at 120°C) takes place mainly by a cascade process, involving one unit of the alkene and three units of the aryl iodide, to afford a substituted 9-phenylsulfonyl-9,10-dihydrophenanthrene, The dominant formation of this 3:1 coupling product, instead of the Heck trisubstituted olefin, shows that aromatic C-H activation processes can compete with the usually fast syn β-hydrogen elimination step in the Heck arylation of an acyclic olefin. The structural scope of this palladium-catalyzed cascade arylation of α,β-unsaturated sulfones has proved to be wide with regard to substitution at the β-position (alkyl, aryl, or alkenyl substitution), substitution at the sulfone unit (alkyl or phenyl sulfones), and configuration at the C=C bond (trans or cis). Moreover, although less favored than in the case of the arylation of α,β-unsaturated sulfones, similarly substituted 9,10-dihydrophenanthrenes have also been obtained in the case of α,β-unsaturated phosphine oxides and α,β-unsaturated phosphonate esters. A Pd0-pdII-pdIV mechanistic pathway involving the successive formation of highly electrophilic σ-alkylpalladium intermediates and palladacycles is proposed for this multi-component arylation.
- Mauleon, Pablo,Nunez, Angel A.,Alonso, Ines,Carretero, Juan C.
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p. 1511 - 1520
(2007/10/03)
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- A New Version of the Peterson Olefination Using Bis(trimethylsilyl)methyl Derivatives and Fluoride Ion as Catalyst
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Reaction between a variety of bis(trimethylsilyl)methyl derivatives and carbonyl compounds under fluoride ion as catalyst is described.The reaction works especially well with nonenolizable carbonyl compounds to give the expected alkenes in high yields and, in some cases, with high stereoselectivity.Application of this methodology to an intramolecular alkenation providing a tricyclic benzocarbacephem ring system is also described.
- Palomo, Claudio,Aizpurua, Jesus M.,Garcia, Jesus M.,Ganboa, Inaki,Cossio, F. P.,et al.
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p. 2498 - 2503
(2007/10/02)
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- Reactions of Arenesulfonyl Chlorides with Olefins Catalyzed by a Ruthenium(II) Complex
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Arenesulfonyl chlorides react with vinylarenes in the presence of dichlorotris(triphenylphosphine)ruthenium(II) catalyst and 1 molar equiv of a tertiary amine to form α,β-unsaturated sulfones 2.Only the E isomers of the sulfones are formed.In reactions of arenesulfonyl chlorides containing an electron-withdrawing Cl or NO2 substituent with α-methylstyrenes, 2-aryl-3-(arylsulfonyl)propenes (5) are also formed.Mechanisms for these reactions are proposed.
- Kamigata, Nobumasa,Sawada, Hideo,Kobayashi, Michio
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p. 3793 - 3796
(2007/10/02)
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