ライフサイエンスコーパス: carbanion

1 termediate of a carbanion mechanism, E(H)H x carbanion-.

2 e in which CO(2) forms along with a residual carbanion.

3 ccepts the negative charge on the developing carbanion.

4 ding the formation of a high energy discrete carbanion.

5 carboxylase to water, which reprotonates the carbanion.

6 ivation to generate an allylic acetate and a carbanion.

7 from electrocyclization of a cyclohexadienyl carbanion.

8 CoM conjugate and carboxylates the resulting carbanion.

9 rotonation of the analogue to form the alpha-carbanion.

10 h hydroxide, ammonia, and methylcyanoacetate carbanion.

11 (oxygenated KH(2)) capable of generating the carbanion.

12 s the substrate alpha-proton to generate the carbanion.

13 cylation of the resulting sulfone-stabilized carbanion.

14 d by alkylation of the newly formed tertiary carbanion.

15 ubstrate, facilitating the formation of a C2 carbanion.

16 ucts resulting from the same thiamin-derived carbanion.

17 1,2-addition of a new TEMPO carbamate methyl carbanion.

18 organometallic trap intercepts the emergent carbanion.

19 ylation and generation of a boron-stabilized carbanion.

20 igration over competing decomposition of the carbanion.

21 ain of Lys-93 to give the enzyme-bound vinyl carbanion.

22 ide elimination of the generated alpha-CF(3) carbanions.

23 direct substitution of alpha-trifluoromethyl carbanions.

24 with a broad range of aromatic carbocations/carbanions.

25 oducing the corresponding cyclic pentadienyl carbanions.

26 adducts obtained using acetonitrile-derived carbanions.

27 is ideally suited for the detection of free carbanions.

28 site-dependent aromaticity of the resulting carbanions.

29 the Ce(IV) cation and reducing tendencies of carbanions.

30 powerful method for the in situ analysis of carbanions.

31 tituents on the nucleophilic reactivities of carbanions.

32 thout consecutive epimerization of two alpha-carbanions.

33 ull-length enzyme from Drosophila in which a carbanion (1.70 A) and an aminoacrylate intermediate (1.

34 nucleophile-specific parameters N and sN of carbanions 1a-e.

35 ) equilibration of the lithiated stereogenic carbanion, (3) conformational inversion during the rearr

36 ehavior of PhCLiRCN as a carbenoid (11) or a carbanion (9) and the importance of LiX formed in situ i

37 compounds were successfully detected as free carbanions A(-) and/or as potassium-bound aggregates [K(

38 In the newly proposed mechanism, the carbanion abstracts a proton from Ser112, thereby comple

39 The carbanion-accelerated Claisen rearrangement has been ext

40 The phosphorus-stabilized, carbanion-accelerated Claisen rearrangements proceed rap

41 cipate in stabilizing negative charge in the carbanion (aci-carboxylate) intermediate.

42 roup in nitromethanes functions as recursive carbanion activator to setup tandem Michael addition-6n-

43 of ester and dicarbonyl compounds involving carbanion addition to nitrosobenzene.

44 miting reaction stage of the starting ketone carbanion addition to propargyl and allenyl systems occu

45 yridyl structure stabilizes the intermediate carbanion, allowing the Michael adduct to be captured by

46 on of the complex of CO(2) and the co-formed carbanion also addresses the mechanism of the uncatalyze

47 ted nitrile nucleophile species (alpha-cyano carbanion analogues), is a key step of the mechanism.

48 emical interaction between the C-site in the carbanion and CO resulted in the superior CO absorption

49 provide a model system for the study of acyl carbanion and homoenolate processes catalyzed by triazol

50 r single-electron transfer) route as well as carbanion and polar-nucleophilic mechanisms.

51 rovide experimental evidence that eliminates carbanion and radical intermediates and conclude that th

52 ed us to follow the decrease of the reactant carbanion and the buildup of the product carbanion in ti

53 hiophenone (3H-S) by a series of delocalized carbanions and by CN(-), and the identity proton transfe

54 expands the synthetic utility of alpha-boryl carbanions and demonstrates their potential in the stere

55 izing the electrostatic interactions between carbanions and lithium cations.

56 nalogous behavior was observed, showing that carbanions and not siliconate complexes are the reactive

57 ability to oscillate between a nucleophilic (carbanion) and an electrophilic (ketone) substrate cente

58 rmediates such as carbenes, carbon radicals, carbanions, and carbocations.

59 Carbanions appear in many organic or biological reaction

60 With sulfur-centered radicals, the carbanions are further functionalized by reaction with e

61 rearrangements of beta-unsaturated sulfinyl carbanions are involved at the key step of those transfo

62 models and enzymes had suggested that these carbanions are resonance-stabilized as enamines.

63 homologues and their ions (carbocations and carbanions) are discussed on the basis of observed simil

64 to this mixture established the alpha-boryl carbanion as the intermediate responsible for C-C bond f

65 reover, the formation of carbon radicals and carbanions as well as the key role of chlorosilanes are

66 C bond in the enzyme environment generates a carbanion at C14.

67 -glucuronate is consistent with a stabilized carbanion at C2 of the substrate during substrate turnov

68 Finally, the carbanion at C2, attacks the electrophilic C1 of the pri

69 ed by a nucleophilic attack of the resultant carbanion at C5 on the AdoMet methyl group.

70 crossover, which enables alkylation through carbanion attack on carbonyl electrophiles.

71 ompetition for a gamma-Cl-aminobutyryl alpha-carbanion between reprotonation and cyclization.

72 ermediate samples between the ketone and the carbanion both interlocked in a tautomeric equilibrium.

73 ichibabin protocol and oxidative coupling of carbanions by copper(I) iodide were used for the macrocy

74 e shifted toward smaller aggregates and free carbanions by the addition of the crown ether 18-crown-6

75 tion coordinate to form the stabilized vinyl carbanion/carbene intermediate, interactions that destab

76 he reactions of the arylsulfonyl-substituted carbanions carrying alpha-chloro and alpha-bromo substit

77 The gas phase stability of carbanions centered at various positions on pyridine N-o

78 vorable deprotonation occurs when the formal carbanion centers are adjacent to each other and then th

79 bridge in the ring plane across two adjacent carbanion centers.

80 lution photoelectron spectra of the simplest carbanions, CH(3)(-) and CD(3)(-).

81 Ph(2)-cyclo-C(3))](-) (IM), which features a carbanion character at C(beta).

82 arboxylates to an alpha-amino radical having carbanion character on carbon; protonation of the latter

83 that the reactive form of the RacE-glutamate carbanion complex, vis-a-vis proton abstraction from C a

84 ing from deborylation to form an alpha-boryl carbanion, deprotonation, and alkoxide addition to form

85 Several tertiary benzylic carbanions derived from enantioenriched 2-aryl heterocyc

86 The relative energies of the rotamers of the carbanions derived from N-methylformamide and methyl N-m

87 o act as a proton donor to the developing C2 carbanion during the reduction of enolpyruvyl-UDP-N-acet

88 compared with those of structurally related carbanions, e.g., Meldrum's acid and dimedone anions.

89 omputed proton affinity of the corresponding carbanions, enabling the intrinsic reversibility of the

90 ought to be necessary for protonation of the carbanion/enamine intermediate, could be replaced by phe

91 N, but involves the transient formation of a carbanion/ene(di)olate intermediate.

92 in the MurB active site, indicative of a C2 carbanion/enol species that is sufficiently long-lived t

93 tering features characteristic of a putative carbanion (enolate) intermediate significantly reduces t

94 he charge-transfer donor is an electron-rich carbanion/enolate intermediate that is generated by the

95 rate binding as well as stabilization of the carbanion/enolate intermediate.

96 des and chlorides with two common stabilized carbanions-enolates of dialkyl malonates and alkyl cyano

97 ploiting 2-lithiofuran as a 4-oxo-2-butenoyl carbanion equivalent provided phospholipids containing g

98 anometallics that can be readily utilized as carbanion equivalents for synthesis.

99 formation of flavin reduction intermediates (carbanion equivalents or adducts), followed by product r

100 ocess features the use of styrenes as latent carbanion equivalents via the intermediacy of catalytica

101 allows the in situ generation of alpha-amino carbanion equivalents which act as nucleophiles.

102 Grignard reagents are commonly used as carbanion equivalents.

103 ble (poly)unsaturated hydrocarbons as latent carbanion equivalents.

104 amental metabolic pathways that require acyl carbanion equivalents.

105 addition, forming an intermediate stabilized carbanion, followed by elimination.

106 lfonylhydrazones yields alpha-functionalized carbanions following the WK-type mechanism.

107 roup is abstracted to generate the requisite carbanion for attack on CO(2).

108 onate, a strong inhibitor of fumarase in its carbanion form, is competitive with both malate and fuma

109 tions to assess uncoupling of gamma-glutamyl carbanion formation and over a range of concentrations o

110 malonyl-ACP in the active site and supports carbanion formation by interacting with the thioester ca

111 ate FLEAL validate reversible gamma-glutamyl carbanion formation by pure carboxylase and indicate the

112 oA with acetoacetyl-CoA requires enolization/carbanion formation from the acetyl C-2 methyl group pri

113 g effects of the 5-fluoro substituent on C-6 carbanion formation in solution (5 kcal/mol) and at ScOM

114 The Glu-215 decarboxylation directs the carbanion formation resulting in the oxidation of the Ty

115 es the formation of the transition state for carbanion formation.

116 ealed that poor coupling was due to impaired carbanion formation.

117 ), suggesting a catalytic role for His160 in carbanion formation.

118 uncoupling of nine out of ten gamma-glutamyl carbanion formations from carboxylative capture, consist

119 ine (DIPEA) at the anode intercepts an alkyl carbanion formed after radical-polar crossover at the ca

120 Lys212 may also stabilize the carbanion formed initially on substrate decarboxylation.

121 mation and chemistry of bromodichloromethide carbanion from CCl(2), the ambiplilicity of CCl(2), the

122 mildly generated alpha,alpha-difluorobenzyl carbanions from electron-deficient aromatics and heteroa

123 Highly efficient CO absorption by carbanion-functionalized ILs provides a new way of separ

124 ly efficient and reversible capture of CO in carbanion-functionalized ionic liquids (ILs) by a C-site

125 een prepared by intramolecular addition of a carbanion generated by deprotonation of a phosphorus sub

126 npolar environment, stabilizes the incipient carbanion generated by the departure of CO(2), and suppl

127 NMR study of this reaction suggests that the carbanion generated from acetonitrile-d(3) in the presen

128 eudocarrier approach to effect addition of a carbanion generated from tracer-level amounts of a radio

129 Treatment of the alpha carbanions generated from several alpha-(pyrimidin-2-yls

130 port the 1,4-addition of alpha,alpha-diboryl carbanions generated via deprotonation of the correspond

131 molecular reaction of dialkyl peroxides with carbanions, generated via chemoselective metal-heteroato

132 The 5'-deoxypyridoxal stabilized glycine carbanion has been generated in water at neutral and mil

133 Procedures that use non-stabilized carbanions have been developed extensively, but these su

134 A wide variety of stabilized carbanions have been found to participate as nucleophile

135 rbenes, halide ions, and phenyldihalomethide carbanions have been spectroscopically characterized and

136 parture of CO(2) by protonation of a vicinal carbanion in a reactive complex.

137 e and later supply a proton to the incipient carbanion in a relatively waterless environment.

138 ansition state, Asp99 protonates the nascent carbanion in a trigonal planar, bis thiol-ligated R-Hg(I

139 Because of its supernucleophilicity, the carbanion in ILs could absorb CO efficiently.

140 gand is accompanied by a placement of the C6 carbanion in the vicinity of the protonated Lys-93 and i

141 ant carbanion and the buildup of the product carbanion in time.

142 ol a practical alternative to stoichiometric carbanions in enantioselective carbonyl reverse prenylat

143 never showed catalytic activity for umpolung carbanions in hydrazone chemistry.

144 ocess to generate alpha,alpha-difluorobenzyl carbanions in the presence of potassium carbonate by exp

145 by the employment of carbonyl-derived alkyl carbanions in various transition-metal catalyzed chemica

146 butenolides was carried out by a nitroalkane carbanion-induced ring opening and relactonization via a

147 ates that the strength of the RacE-glutamate carbanion interaction energy is highly distributed among

148 xidation step is initiated by formation of a carbanion intermediate and that a hydroperoxide (anion)

149 hese results support a mechanism involving a carbanion intermediate but are difficult to reconcile wi

150 effect of the fluorine, which stabilizes the carbanion intermediate by electron withdrawal and produc

151 yzed deprotonation of FUMP to form the vinyl carbanion intermediate common to OMPDC-catalyzed reactio

152 a position where it is able to stabilize the carbanion intermediate formed by the methyl group of the

153 o the role of the residue in stabilizing the carbanion intermediate formed during enzymatic catalysis

154 id could only trap only the enamine/C2 alpha-carbanion intermediate in an intramolecular model, and w

155 ctrostatic stabilization of the zwitterionic carbanion intermediate is afforded by the close position

156 results have shown that the stability of the carbanion intermediate is not a critical factor in the r

157 oceed via an E1cB-like pathway, in which the carbanion intermediate is stabilized by an enzyme oxyani

158 ure of a half-curcumin is the formation of a carbanion intermediate of its acetylacetone moiety, open

159 Furthermore, the carbanion intermediate of the 1,2-Brook rearrangement ca

160 r by stabilization of the enzyme-bound vinyl carbanion intermediate of the stepwise reaction.

161 surements are consistent with reaction via a carbanion intermediate or a concerted reaction with a "c

162 -1 in the enzymatic mechanism and suggests a carbanion intermediate stabilized by simple electrostati

163 s placed on the interaction of the glutamate carbanion intermediate with RacE.

164 states that lead to formation of this vinyl carbanion intermediate, and that there is a large ca. (1

165 One involves a transient carbanion intermediate, formed by attack of water or a h

166 (2)) oxygenation to convert glutamate into a carbanion intermediate, which subsequently attacks CO(2)

167 has been established to involve a stabilized carbanion intermediate.

168 ts, which have been shown to destabilize the carbanion intermediate.

169 arge-consistent with a mechanism involving a carbanion intermediate.

170 for this enzyme involves the formation of a carbanion intermediate.

171 roton at C2alpha to form the enamine-C2alpha-carbanion intermediate.

172 r, is postulated to be 2 proton donor to the carbanion intermediate.

173 energy barrier preceding the gamma-glutamyl carbanion intermediate.

174 udies suggest the intermediacy of a discrete carbanion intermediate.

175 turns it subsequently to the postcleavage Ca-carbanion intermediate.

176 s it subsequently to the postcleavage Calpha-carbanion intermediate.

177 talytic mechanism involving an alpha-carboxy-carbanion intermediate/transition state, which is consis

178 able zwitterionic (oxocarbenium cation/vinyl carbanion) intermediate, which undergoes nucleophilic ad

179 nn reaction, enabling the detection of their carbanion intermediates by desorption electrospray ioniz

180 an oxygen activation mechanism that involves carbanion intermediates in these materials.

181 ns and nonconcerted mechanisms with discrete carbanion intermediates is very difficult experimentally

182 odroplets can capture and stabilize reactive carbanion intermediates isolated from four classic organ

183 well as the stability of their corresponding carbanion intermediates was determined.

184 c ORR is determined by the generation of the carbanion intermediates, and the current by the rate the

185 -enyl-4-diphosphate via discrete radical and carbanion intermediates.

186 troreductive generation of alkyl radical and carbanion intermediates.

187 ine intermediates in which a substrate-based carbanion is an obligatory intermediate.

188 For 13, generation of the alpha-sulfonamide carbanion is possible and regiospecific oxidation with c

189 This suggests that the carbanion is stabilized by glycal formation, concomitant

190 ormation of the highly charged tetra-reduced carbanion is stabilized through Li(+) coordination under

191 ealization that halogen transfer to unstable carbanions is an enabling principle across diverse C(sp(

192 Conjugate addition of alpha-boron-stabilized carbanions is an underexplored reaction modality.

193 Fluorination of carbanions is pivotal for the synthesis of fluorinated c

194 ta-Hydride elimination from the formed alkyl carbanions lead to their desorption as alkene products i

195 sis suggesting an acid-base mechanism with a carbanion-like intermediate that could account for the a

196 on is used in the stabilization of the vinyl carbanion-like transition state common to the decarboxyl

197 0.026 M(-)(1) s(-)(1)) shows that the vinyl carbanion-like transition state is stabilized by 3.5 kca

198 to a 5.8 kcal/mol stabilization of the vinyl carbanion-like transition state, which is similar to the

199 intermediate or a concerted reaction with a "carbanion-like" transition state.

200 In addition, we analyze the role of a carbanion lone pair in the rearrangement step, concludin

201 nsistent with the expected intermediate of a carbanion mechanism, E(H)H x carbanion-.

202 edure involving (i) phosphonylation and (ii) carbanion-mediated phosphonate intramolecular cyclizatio

203 By modifying the structure of the carbanion nucleophile, an asymmetric vinylogous aza-Darz

204 ore reactive than oxoesters toward amine and carbanion nucleophiles, respectively.

205 beta-position reveal that ionization of the carbanion occurs to form a tight ion-pair with high rete

206 jor role in activating OAA to react with the carbanion of acetyl-CoA.

207 d by the Katritzky salt and the alpha & beta carbanion of malononitrile-aided ketones, which permits

208 The carbanion of that intermediate then attacks the OAA carb

209 ere synthesized by similar alkylation of the carbanions of appropriate 4-carboxyphenylacetic, (5-carb

210 LACa indicates that nucleophilic attack by a carbanion or amine on the ligand will likely occur while

211 s, carbon disulfide, and carbon dioxide with carbanions or enamines (reference nucleophiles) have bee

212 ive coupling as an alternative to pre-formed carbanions or metallic reductants in C=X addition.

213 on of recent syntheses that have implemented carbanion- or radical-based fragment couplings to form c

214 on of recent syntheses that have implemented carbanion- or radical-based fragment couplings to form c

215 kage at all three rings of TGE suggests a C5 carbanion, para to the C2 phenolate oxygen, as the carbo

216 re a common reaction mechanism, in which the carbanion participating in the condensation reaction is

217 r the alkyl Grignard reagents and possibly a carbanion pathway for aryl Grignard reagents.

218 r of coordinated ligand between faces of the carbanion plane as well as a lithium-exchange process.

219 intermediates (including the enamine/C2alpha-carbanion present on all such enzymes) was tested experi

220 mode of action, the study of catalytic acyl carbanion processes has been an area of immense interest

221 Fluorinated 2-(p-tolylsulfinyl)benzyl carbanions react with allyl and propargyl halides in a h

222 At pH < 7, this carbanion reacts mainly with the carbonyl carbon of 1 to

223 The resulting benzylic carbanion reacts with CO(2) to generate the correspondin

224 At pH > or = 8, this carbanion reacts with the iminium carbon of the pyridoxa

225 Product and carbanion reagent studies suggest that the 3(2H)-furanon

226 , so that ScOMPDC stabilizes the bound vinyl carbanions, relative to the bound nucleotides, by at lea

227 rol experiments support the proposed radical-carbanion relay mechanism.

228 ionalization of carbonyl groups by a radical-carbanion relay sequence (photo-Wolff-Kishner reaction).

229 with purified carboxylase showed very little carbanion reprotonation and consequently revealed the de

230 Cyanide stimulated Glu deprotonation and carbanion reprotonation to the same extent in wild type

231 arnessing the phase-changing behavior of the carbanion salts in ether solutions upon reacting with CO

232 environment is known to rapidly annihilate a carbanion species, reducing its lifetime to as short as

233 ct of a nitrogen-centered positive charge on carbanion stability was assessed.

234 ssistance of the inner water molecule in the carbanion stabilization of endofullerene is proposed.

235 iously demonstrated to play a direct role in carbanion stabilization, and thus the large carbon isoto

236 ment has been extended to include phosphorus carbanion-stabilizing groups.

237 s it could provide for stable storage of the carbanion state, or whether this feature represents a sp

238 prozin was prepared using the alpha-sulfonyl carbanion strategy along with optimized desulfonylation.

239 ad of a classical HAT process, to generate a carbanion that can be terminated by protonation from sol

240 dent steps (i.e. Glu deprotonation to form a carbanion that then reacts with CO(2)), based on previou

241 base in thiamin-aldehyde adducts, producing carbanions that could incorporate dissolved CO(2) into c

242 nd utilizing transient alpha-trifluoromethyl carbanions that relies on a neighbouring cationic pai-al

243 In addition, we examined two further carbanions that were suggested to form stable CO(2) addu

244 amin diphosphate (the "ThDP-enamine"/C2alpha-carbanion, the first postdecarboxylation intermediate) w

245 ly favored Si-F bond formation to generate a carbanion, therefore enabling the highly efficient and s

246 nitrido ligand, followed by migration of the carbanion to nitrogen.

247 the heteroarene, addition of the heteroarene carbanion to the silyl ether, and dissociation of tert-b

248 s that can monooxygenate malononitrile alpha-carbanions to afford activated acyl cyanides capable of

249 C-C bonds by the addition of derivatives of carbanions to carbonates.

250 cular nucleophilic addition of sulfonimidoyl carbanions to form benzothiazines.

251 contrast, the addition of intermediate alpha-carbanions to the terminal position of methyl allenyl et

252 t hydrogens, the propensity of the resulting carbanions to undergo alpha-elimination of fluoride rend

253 te ODC x I(-) is achieved by movement of the carbanion toward the external cation Lys-93 on decarboxy

254 from a C-C bond to a hypothetical tert-butyl carbanion, toward the reference electrophile to be about

255 as both Bronsted base and acid, involving a carbanion-type transition state.

256 Stabilized carbanions undergo an uncommon 3-exodig cyclization onto

257 that chiral 3-substituted gamma-sultam alpha-carbanions undergo diastereoselective alkylation reactio

258 ially produced 1,3-betaine (o-sulfonium/aryl carbanion) undergoes intramolecular proton transfer to g

259 for simple hydrocarbons which give localized carbanions upon deprotonation there is an apparent linea

260 surrogates of benzyl anions and alpha-silyl carbanions utilized for nucleophilic addition and Peters

261 A method for the generation of tertiary carbanions via a deaminative radical-polar crossover is

262 rolled electrophilic trapping of alpha-boryl carbanions via the selective anionic ring-opening of ste

263 t entails the generation of alpha-oxygenated carbanions via the umpolung process.

264 wild-type enzyme and proposed herein to be a carbanion, was not observed during hydrolysis by H265Q.

265 ydrofuran or methanol was used as a solvent, carbanions were also successfully observed.

266 These carbanions were reacted with a range of neopentyl boroni

267 of a proton from the nitroalkane, forming a carbanion which adds to the flavin N(5).

268 required for generation of the C2-thiazolium carbanion which attacks the donor substrate.

269 sence of LDA to produce a stable alpha-amino carbanion which was condensed on a large variety of alky

270 es bearing N'-alkenyl substituents generates carbanions which undergo intramolecular migration of the

271 a nucleophilic addition of a phenylacetamide carbanion, which is generated in the presence of tert-bu

272 n the acrylate olefin to generate a reactive carbanion, which participates in multiple pathways, incl

273 yl ether results in C-O cleavage to afford a carbanion, which reacts with a number of electrophiles f

274 ore substituted alkyl halide gives rise to a carbanion, which undergoes preferential coupling with a

275 idated through experimental methods for five carbanions, which include three stable and two unstable

276 r solvents, such as pure water, in capturing carbanions, which is in contrast to the earlier report t

277 -BuLi, followed by reaction of the resulting carbanion with methyl esters of N-protected l-amino acid

278 nds correlate the stability of the resulting carbanion with reaction efficiency.

279 ctron acceptor, and a substrate radical or a carbanion with substantial radical character participate

280 zed to be potential overlap of the incipient carbanion with the pi-orbitals of both the PLP and the v

281 ation of easy manageable lithium a-bis(boryl)carbanions with carbonyl derivatives, the so-called boro

282 n of easy manageable lithium alpha-bis(boryl)carbanions with carbonyl derivatives, the so-called boro

283 The designed ionic liquids (ILs) containing carbanions with conjugated and asymmetric structure, dep

284 reaction of sulfone- and nitrile-stabilized carbanions with dialkyl peroxides, triethylsilyl/alkyl p

285 This provided a unique series of nanosized carbanions with increasing negative charge for in-depth

286 The reaction of o-sulfinylbenzyl carbanions with prochiral Michael acceptors, such as dif

287 f a series of reactions of alpha-substituted carbanions with reference electrophiles to elucidate the

288 heir derivatives, and ions (carbocations and carbanions)-with studied terrestrial chemistry.

289 nal acetylenes followed by an intramolecular carbanion-yne cyclization in a 5-exo-dig manner and subs