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

3 organometallic trap intercepts the emergent carbanion.

4 from electrocyclization of a cyclohexadienyl carbanion.

5 CoM conjugate and carboxylates the resulting carbanion.

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

7 h hydroxide, ammonia, and methylcyanoacetate carbanion.

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

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

10 ylation and generation of a boron-stabilized carbanion.

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

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

13 ccepts the negative charge on the developing carbanion.

14 ding the formation of a high energy discrete carbanion.

15 carboxylase to water, which reprotonates the carbanion.

16 ivation to generate an allylic acetate and a carbanion.

17 with a broad range of aromatic carbocations/carbanions.

18 oducing the corresponding cyclic pentadienyl carbanions.

19 tituents on the nucleophilic reactivities of carbanions.

20 thout consecutive epimerization of two alpha-carbanions.

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

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

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

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

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

26 The carbanion-accelerated Claisen rearrangement has been ext

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

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

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

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

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

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

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

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

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

36 izing the electrostatic interactions between carbanions and lithium cations.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

73 amental metabolic pathways that require acyl carbanion equivalents.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

118 -1 in the enzymatic mechanism and suggests a carbanion intermediate stabilized by simple electrostati

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

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

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

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

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

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

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

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

127 energy barrier preceding the gamma-glutamyl carbanion intermediate.

128 has been established to involve a stabilized carbanion intermediate.

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

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

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

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

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

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

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

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

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

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

139 0.026 M(-)(1) s(-)(1)) shows that the vinyl carbanion-like transition state is stabilized by 3.5 kca

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

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

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

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

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

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

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

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

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

149 The carbanion of that intermediate then attacks the OAA carb

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

176 cular nucleophilic addition of sulfonimidoyl carbanions to form benzothiazines.

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

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

179 Stabilized carbanions undergo an uncommon 3-exodig cyclization onto

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

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

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

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

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

185 These carbanions were reacted with a range of neopentyl boroni

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

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

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

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

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

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

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

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

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

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

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

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