Vicarious nucleophilic substitution of hydrogen in electrophilic alkenes

Mąkosza, M.; Kwast, Andrzej

doi:10.1016/s0040-4020(01)80963-7

Cited by 24 publications

(16 citation statements)

References 29 publications

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“…3-Acyl-2 H -1-benzopyran-2-ones 268 reacted with phenacyl bromide in the presence of a base to give the cyclopropane derivatives 271 and 272 in moderate yields via intermediates 269 and 270 [ 511 , 512 , 513 , 514 , 515 , 516 , 517 , 518 ]. The mechanism and the stero-selectivity of such reactions have been well-studied ( Scheme 79 ) [ 511 ].…”

Section: Reactions Of α-Haloketones With Alkenes and Alkynesmentioning

confidence: 99%

The Chemistry of α-Haloketones and Their Utility in Heterocyclic Synthesis

2003

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Section: Reactions Of α-Haloketones With Alkenes and Alkynesmentioning

confidence: 99%

The Chemistry of α-Haloketones and Their Utility in Heterocyclic Synthesis

2003

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“…Diethyl (1-dimethyl[phenyl]silylvinyl)ethylmalonate 5c. Procedure as described for the preparation of 5b; yield 79% (found: C, 65.22; H, 8.27 2H, q, J = 7.1 Hz, MeCH 2 OCO), 4.12 (2 H, q, J = 7.1 Hz, MeCH 2 OCO), 5.67 (1 H,s,SiC=CH), 5.91 (1 H,s,m,Ar); d C (50 MHz, CDCl 3 ) −0.32 (2 C), 9.44, 13.92 (2 C), 28.57, 61.07 (2 C), 63.72, 127.42 (2 C), 128.53, 130.80, 134.02 (2 C), 140.09, 147.52 and 171.00 (2 C); m/z (EI) 333 (M + − Me, 33%), 303 (5), 275 (16), 271 (59), 259 (13), 233 (12), 215 (32), 187 (42), 159 (87), 153 (48), 135 (100), 141 (33), 125 (46), 121 (22), 107 (20), 105 (71), 95 (38), 91 (30), 77 (33) and 75 (73).…”

Section: Diethyl (1-dimethyl[phenyl]silylvinyl)methylmalonate 5bmentioning

confidence: 99%

“…Diethyl methyl(1-phenylvinyl)malonate 5g. Procedure as described for the preparation of 5b; yield 73% (found: C, 69.30; H, 7.52 22.26, 60.03, 61.59 (2 C), 118.03, 127.34, 127.82 (2 C), 128.24 (2 C), 140.76, 147.78 and 171.33 (2 C); m/z (EI) 276 (M + , 0.5%), 231 (0.5), 203 (100), 185 (11), 175 (89), 147 (16), 129 (64), 115 (33) and 91 (27).…”

Section: Diethyl Benzyl(1-dimethyl[phenyl]silylvinyl)malonatementioning

confidence: 99%

The unprecedented reaction of dimethylsulfonium methylide with Michael acceptors: synthesis of 1-substituted vinyl silanes and styrenes

2005

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Rather than the usual cyclopropanation, conditions for an unprecedented elimination reaction from the adduct of dimethylsulfonium methylide and various Michael acceptors have been established leading to functionalized 1-substituted alkenes. In silyl substituted substrates (2a and 2h), where a facile Peterson-type olefination is possible from the adduct; elimination took place instead to give functionalized 1-substituted vinyl silanes. Aryl substituted Michael acceptors (2b-e, 2g and 2i-k) also underwent a similar kind of olefination to give 1-substituted styrene derivatives with moderate yields along with a side product, which arose by nucleophilic demethylation from the adduct of dimethylsulfonium methylide and arylidene malonates. Hammett studies revealed that selectivity for olefination vs. demethylation increases as the aryl substituent becomes more electron deficient. Alkylidene malonates (2f and 2l) with a beta-alkyl substituent did not favour the olefination process. Sequential addition of Michael acceptors and alkyl halides to a mixture of dimethylsulfonium methylide and sodium dimsylate provided olefination followed by alkylation on the active methine group. A mechanistic pathway has been formulated from the studies of a few sulfonium methylides.

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“…Later, the scope was extended to electrophilic heterocyclic compounds as well as electrophilic alkenes. [7,8] Numerous C, N, and O anions were applied as nucleophilic substrates for VNS. The general scheme of the reaction involves nitrosubstituted arenes that form σ H adducts, which then undergo base-promoted 1,2-elimination of HX (Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

Vicarious Nucleophilic Substitutions of Hydrogen in 1,1,1‐Trifluoro‐N‐[oxido(phenyl)(trifluoromethyl)‐λ⁴‐sulfanylidene]methanesulfonamide

2008

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1,1,1‐Trifluoro‐N‐[oxido(phenyl)(trifluoromethyl)‐λ4‐sulfanylidene]methanesulfonamide reacts with carbanions bearing a leaving group to give vicarious nucleophilic substitution (VNS) of hydrogen products with moderate yields. This is the first example of the VNS process at a benzene ring activated by an electron‐withdrawing group other than a nitro group. The orientation of the substitution is exclusively para. Findings open a large possibility for exploration of the scope of the VNS reaction on to compounds activated with sulfur‐based electron‐withdrawing groups. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

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Vicarious nucleophilic substitution of hydrogen in electrophilic alkenes

Cited by 24 publications

References 29 publications

The Chemistry of α-Haloketones and Their Utility in Heterocyclic Synthesis

The Chemistry of α-Haloketones and Their Utility in Heterocyclic Synthesis

The unprecedented reaction of dimethylsulfonium methylide with Michael acceptors: synthesis of 1-substituted vinyl silanes and styrenes

Vicarious Nucleophilic Substitutions of Hydrogen in 1,1,1‐Trifluoro‐N‐[oxido(phenyl)(trifluoromethyl)‐λ⁴‐sulfanylidene]methanesulfonamide

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Vicarious nucleophilic substitution of hydrogen in electrophilic alkenes

Cited by 24 publications

References 29 publications

The Chemistry of α-Haloketones and Their Utility in Heterocyclic Synthesis

The Chemistry of α-Haloketones and Their Utility in Heterocyclic Synthesis

The unprecedented reaction of dimethylsulfonium methylide with Michael acceptors: synthesis of 1-substituted vinyl silanes and styrenes

Vicarious Nucleophilic Substitutions of Hydrogen in 1,1,1‐Trifluoro‐N‐[oxido(phenyl)(trifluoromethyl)‐λ4‐sulfanylidene]methanesulfonamide

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Vicarious Nucleophilic Substitutions of Hydrogen in 1,1,1‐Trifluoro‐N‐[oxido(phenyl)(trifluoromethyl)‐λ⁴‐sulfanylidene]methanesulfonamide