ライフサイエンスコーパス: sigmatropic

1 h cyclobutane ring cleavage to 12-annulenes, sigmatropic 1,5-H-shifts, electrocyclic ring-openings of

2 hylbenzo-2,3-diazafulvenium methides undergo sigmatropic [1,8]H shifts allowing the efficient synthes

3 Furthermore, the possibility of a [1,5] sigmatropic alkyl group shift of bicyclo[4.2.0]octa-2,4-

4 ll singlet biradical-mediated stepwise [1,5] sigmatropic alkyl group shift were shown to be comparabl

5 cyclo[2.2.2]oct-2-ene (2) via a formal [1,3] sigmatropic carbon migration.

6 clobutene into biaryl occurs through a [1,3] sigmatropic carbon shift followed by [4+2] cycloextrusio

7 oes not govern stereochemistry for the [1,3] sigmatropic carbon shifts.

8 l or alkylidene groups to participate in the sigmatropic event.

9 This reaction is a hybrid of a [1,2] sigmatropic hydrogen shift and a two-electron electrocyc

10 in D to vitamin D is an intramolecular [1,7]-sigmatropic hydrogen shift with antarafacial stereochemi

11 groups capable of participating in the [1,7]-sigmatropic hydrogen shift.

12 esponding allylic amines via Overman's [3,3]-sigmatropic imidate rearrangement, and subsequent one-po

13 rting the predominance of a concerted [3, 3] sigmatropic mechanism.

14 rules are somewhat permissive for the [1,3] sigmatropic migration of carbon.

15 yield by a cascade mechanism that involves a sigmatropic migration, elimination, electrocyclization s

16 hat the transition structures of these [2,3]-sigmatropic migrations are aromatic.

17 tion of which is a formal 10-electron double sigmatropic, or dyotropic, rearrangement.

18 However, the stepwise sigmatropic pathway is suggested to only be feasible for

19 rences in barriers between electrocyclic and sigmatropic pathways.

20 lution counterpart, are thus concerted [3,3]-sigmatropic processes in which C-C bond formation lags b

21 derivatives indicate that both are concerted sigmatropic processes, controlled by the orientation of

22 quinone pK(a) values by plotting the percent sigmatropic products versus pH.

23 e activity, suggests that MbtI may exploit a sigmatropic pyruvate elimination mechanism similar to th

24 nal work, the first example of a bifurcating sigmatropic reaction featuring a bispericyclic transitio

25 ted and 7-methoxy substituents favor the 1,5-sigmatropic reaction.

26 essentially pericyclic), the 11 --> 12 [3,3] sigmatropic rearrangement (pseudopericyclic), and simila

27 featuring a Rh-mediated O-H insertion/[3,3]-sigmatropic rearrangement and subsequent alpha-ketol rea

28 nder the latter conditions resulted in [1,3]-sigmatropic rearrangement and subsequent oligomerization

29 s an additive increase the rate of the [3,3] sigmatropic rearrangement as well as the diastereoselect

30 The tandem ylide formation/[2,3]-sigmatropic rearrangement between donor/acceptor rhodium

31 Subsequent in situ enantioselective [2,3]-sigmatropic rearrangement catalyzed by the isothiourea b

32 nsient allenes by means of a strategic [2,3]-sigmatropic rearrangement followed by trapping of the re

33 e strategy is based on a [3,3]-allyl cyanate sigmatropic rearrangement from enantioenriched gamma-hyd

34 tero-Diels-Alder cycloadditions as well as a sigmatropic rearrangement have been located, and they al

35 hat rapidly undergoes either [3,3]- or [5,5]-sigmatropic rearrangement in one-pot to form a 2-amino-2

36 tion pathway provides rare examples of [2,3]-sigmatropic rearrangement in this class of compounds as

37 isomerization process that occurs via [3,3]-sigmatropic rearrangement induced by high oxidation stat

38 roduct is formed via an intramolecular [3,3]-sigmatropic rearrangement instead of the previously prop

39 ies on CaADH, while the exceptionally facile sigmatropic rearrangement is expected to drive computati

40 consistent with the observation that the 2,3-sigmatropic rearrangement is favored with donor/acceptor

41 A subsequent [3,3]-sigmatropic rearrangement is followed by intramolecular

42 ketyl radical-anion mechanism for the [3,3]-sigmatropic rearrangement is presented.

43 ions precedes a stereochemistry-determining sigmatropic rearrangement is reported.

44 hat the lowest energy pathway for each [3,5]-sigmatropic rearrangement is via an allowed, concerted p

45 N-Allyl enamines can undergo a [3,3] sigmatropic rearrangement known as a 3-aza-Cope (or amin

46 cond domino process, a [H]-shift and a [3,3]-sigmatropic rearrangement lead to the aromatization of t

47 tractive and highly diastereoselective [2,3]-sigmatropic rearrangement occurs when N-methyl-1,2,3,6-t

48 talin 55 is the oxyanionic-accelerated [3,3]-sigmatropic rearrangement of 37e.

49 heir alpha-position by an asynchronous [3,3]-sigmatropic rearrangement of a mixed acetal species whic

50 ds (78-89%) in a process involving the [1,4]-sigmatropic rearrangement of a nitrile-stabilized ammoni

51 dihydroxylation, and a stereoselective [2,3]-sigmatropic rearrangement of a selenoxide to effect a 1,

52 wn to be an effective catalyst for the [3,3]-sigmatropic rearrangement of a variety of substituted al

53 NEPHOS(AuCl)(2)), has been developed for the sigmatropic rearrangement of alkenyl-methylenecyclopropa

54 ve mechanisms of the gold(I)-catalyzed [3,3] sigmatropic rearrangement of allenyl vinyl ethers by den

55 development of an efficient oxidative [2,3]-sigmatropic rearrangement of allylic hydrazides, via sin

56 The [2,3]-sigmatropic rearrangement of allylic sulfoxides to allyl

57 Under certain conditions, the [2,3]-sigmatropic rearrangement of allyloxy carbonyl compounds

58 se of phase-transfer catalysis for the [2,3]-sigmatropic rearrangement of allyloxy carbonyl compounds

59 (II)-catalyzed oxonium ylide formation-[2,3] sigmatropic rearrangement of alpha-diazo-beta-ketoesters

60 abicyclo[5.3.0]decane ring system by a [3,3] sigmatropic rearrangement of an acylimmonium ion followe

61 conocene-promoted ring contraction and [3,3] sigmatropic rearrangement of an enynol.

62 eveloped via a dichlorocarbene insertion and sigmatropic rearrangement of an in situ generated ylide.

63 We find the barrier for sigmatropic rearrangement of chemisorbed hydrogen atoms

64 ence for a mechanism that involves the [3,3] sigmatropic rearrangement of divinylcyclopropanes.

65 he scope of the NCS-mediated amination/[2,3]-sigmatropic rearrangement of enantioenriched allylic sel

66 ed to the allylic amines via Overman's [3,3]-sigmatropic rearrangement of imidates.

67 systems are prepared by acid-catalyzed [3,3]-sigmatropic rearrangement of O-aryloximes.

68 nsformed directly to allenes through a [2,3]-sigmatropic rearrangement of propargyl phosphites.

69 mparative study of the Au(I)-catalyzed [3,3]-sigmatropic rearrangement of propargylic esters and prop

70 Sigmatropic rearrangement of spirocyclic pyrazoles to fu

71 er-catalyzed generation and subsequent [2,3]-sigmatropic rearrangement of sulfur ylides is strongly d

72 Products are obtained by [3,3]-sigmatropic rearrangement of the azasulfonium enolate or

73 Instead, a [3,3]-sigmatropic rearrangement of the initial cyclization int

74 ith the N-Boc-oxaziridine 1 results in [2,3]-sigmatropic rearrangement of the intermediate allylic N-

75 Quantum chemical calculations of a [3,3]sigmatropic rearrangement of the N,O-divinyl hydroxylami

76 rs at the terminal oxygen, followed by [2,3]-sigmatropic rearrangement of the pendant allyl group, in

77 The mechanism involves a [2,3]-sigmatropic rearrangement of the respective selenoxides

78 bsolute stereochemistry and (ii) a new [3,3]-sigmatropic rearrangement of the thiono-Claisen variety

79 The 2,3-sigmatropic rearrangement proceeds through initial cleav

80 reochemically unscathed by competitive [3,3]-sigmatropic rearrangement processes.

81 C gives a modest yield of the initial [3,5]-sigmatropic rearrangement product, 2,6-diacetoxy-6-methy

82 refore affords the radical anion without any sigmatropic rearrangement products.

83 he semiquinone which is rapidly converted to sigmatropic rearrangement products.

84 The first example of a biocatalytic [2,3]-sigmatropic rearrangement reaction involving allylic sul

85 s-alkenes is evidenced by their formal [1,3]-sigmatropic rearrangement reactions and the rapid additi

86 s via stereocontrolled cyanate-to-isocyanate sigmatropic rearrangement reactions of the corresponding

87 rgo thermal and photolytic cycloaddition/1,5-sigmatropic rearrangement reactions with 11a-d with N(2)

88 engineered to initiate a sulfimidation/[2,3]-sigmatropic rearrangement sequence in whole E. coli cell

89 rignard ring opening/allylic sulfoxide [2,3]-sigmatropic rearrangement sequence previously developed

90 f kinetic resolution, and the stereospecific sigmatropic rearrangement step, which proceeds with full

91 cyclo[4.2.0]oct-2-ene (1a) undergoes a [1,3] sigmatropic rearrangement to 5-exo- and 5-endo-methoxybi

92 cyclo[4.2.0]oct-2-ene (1a) undergoes a [1,3] sigmatropic rearrangement to 5-methylbicyclo[2.2.2]oct-2

93 binaphthyl hydrazines undergo a facile [3,3]-sigmatropic rearrangement to afford enantiomerically enr

94 The route relies on the aza-[2,3]-Wittig sigmatropic rearrangement to efficiently install the rel

95 incipally via SO2-N bond homolysis and [1,5] sigmatropic rearrangement to generate 37, 10 proceeded v

96 ive trans-1,3-pentadiene, 40 +/- 3% of [3,3]-sigmatropic rearrangement to give cis-3-penten-2-yl acet

97 give cis-1,3-pentadiene, 32 +/- 2% of [3,3]-sigmatropic rearrangement to give trans-3-penten-2-yl ac

98 lled stereoselective Mislow-Evans-type [2,3]-sigmatropic rearrangement to install the C5 stereocenter

99 cycloaddition participate in a thermal [3,3] sigmatropic rearrangement to yield bicyclo[3.3.2]decadie

100 The most favored [3,3]-sigmatropic rearrangement transition state is bimodal, l

101 Several [3,3] sigmatropic rearrangement transition states were also lo

102 ged 16-acetate (2), which can form from 1 by sigmatropic rearrangement under basic conditions, batrac

103 sors are readily prepared and undergo smooth sigmatropic rearrangement upon exposure to iodosobenzene

104 n demonstrated by combining the Mislow [2,3]-sigmatropic rearrangement with catalytic asymmetric hydr

105 These systems undergo the [3,3] sigmatropic rearrangement with high selectivity, with a

106 lowed by a probable 1,3-OAc migration ([3,3]-sigmatropic rearrangement).

107 om an unexpected and remarkably facile [1,3]-sigmatropic rearrangement, and a tactic to disfavor the

108 via a gold-catalyzed tautomerization, [3,3]-sigmatropic rearrangement, and cyclodehydration process.

109 ocyclization of the hexatriene system, [1,9]-sigmatropic rearrangement, and heterocyclic ring opening

110 as the tandem cyclization followed by [2,3]-sigmatropic rearrangement, as well as cyclization of the

111 cyclopropenation, sulfur ylide formation/2,3-sigmatropic rearrangement, as well as nitrogen ylide for

112 cluding [2 + 2] photocycloaddition and [3,3] sigmatropic rearrangement, indicating the possibility fo

113 rhodium-bound oxonium ylide formation, [2,3]-sigmatropic rearrangement, oxy-Cope rearrangement, enol-

114 on to N-fused pyrroles proceeded via a [3,3]-sigmatropic rearrangement, the analogous cycloisomerizat

115 The disfavored [3,3]-sigmatropic rearrangement, which would produce the unobs

116 rmed through the use of a Still-Wittig [2,3]-sigmatropic rearrangement, while the trans mimic, the (E

117 gold catalyzed enantioselective tandem [3,3]-sigmatropic rearrangement-[2+2]-cyclization.

118 ations is combined with a diastereoselective sigmatropic rearrangement.

119 oxonium ylide formation followed by a [2,3]-sigmatropic rearrangement.

120 described as a concerted asynchronous [3,3]-sigmatropic rearrangement.

121 mixed acetal formation and subsequent [3,3] sigmatropic rearrangement.

122 rmediate and facilitates the rate of the 3,3-sigmatropic rearrangement.

123 4 + 2) cyclohexenyl products through a [3,3]-sigmatropic rearrangement.

124 dolines via a thionium ylide-initiated [3,3]-sigmatropic rearrangement.

125 through the use of an Ireland-Claisen [3,3]-sigmatropic rearrangement.

126 a mixture of regioisomers upon heating via a sigmatropic rearrangement.

127 nverted to 3-hydroxy tetrahydropyridines via sigmatropic rearrangement.

128 luorescent indicator based on the 2-aza-Cope sigmatropic rearrangement.

129 pansion of the anionic intermediate by [1,3] sigmatropic rearrangement.

130 ate of hydrogenation relative to the rate of sigmatropic rearrangement.

131 titution via suprafacial allylic azide [3,3]-sigmatropic rearrangement.

132 e species becomes competitive with the [3,3]-sigmatropic rearrangement.

133 ilable tartrate derivative were obtained via sigmatropic rearrangement.

134 s formed immediately after the initial [3,3] sigmatropic rearrangement.

135 of oxonium ylide formation followed by [2,3]-sigmatropic rearrangement.

136 (+)-latifoline (1) employing a tandem [3,3] sigmatropic rearrangement/[1,2] allyl shift as a key ste

137 lines efficiently from silver-mediated [3,3]-sigmatropic rearrangement/Diels-Alder reaction of 1,9-di

138 of a stereoselective one-pot oxidative [3,3] sigmatropic rearrangement/Friedel-Crafts arylation that

139 KOtBu-induced E2 elimination, undergo [3,3]-sigmatropic rearrangement/intramolecular 5-exo-dig cycli

140 gement (pseudopericyclic), and similar [3,3] sigmatropic rearrangements (all pericyclic), and detaile

141 0(2,8)]tridec-10-ene (13TCT) undergoes [1,3] sigmatropic rearrangements at 315 degrees C in the gas p

142 [3,3]-Sigmatropic rearrangements have been widely utilized for

143 rong experimental evidence that direct [3,5]-sigmatropic rearrangements in these molecules are favore

144 Results of calculations on the [3,3] sigmatropic rearrangements involving additional transiti

145 Earlier studies have shown that [3,3]-sigmatropic rearrangements of allyl esters are useful fo

146 The [2,3]- and [1,2]-sigmatropic rearrangements of ammonium ylides are studie

147 [2,3]-Sigmatropic rearrangements of beta-unsaturated sulfinyl

148 l computational study of the concerted [3,3] sigmatropic rearrangements of cis-1-iminyl-2-ketenylcycl

149 ta- and delta-eliminations, as well as [3,3]-sigmatropic rearrangements of esters are primarily pseud

150 rroles has been achieved via [3,3] and [1,3] sigmatropic rearrangements of O-vinyl oximes, respective

151 relative rate constants for ring opening and sigmatropic rearrangements of the dihydrophenanthrene in

152 of dynamic trajectories in [1,2]- and [2,3]-sigmatropic rearrangements suggests a counterintuitive a

153 The carbene undergoes two [1,2]-sigmatropic rearrangements via competing 1,2-C atom shif

154 Three sigmatropic rearrangements were employed in building the

155 esting and unexpected [1,2]-Wittig and [1,3]-sigmatropic rearrangements were identified during the op

156 no-Claisen variety that is among the fastest sigmatropic rearrangements yet reported.

157 arrangements, as well as some typical [2, 3]-sigmatropic rearrangements, e.g., thermal rearrangements

158 e failed, we uncovered another set of tandem sigmatropic rearrangements, leading to vinyl imidate for

159 Here, using a series of sequential [3,3]-sigmatropic rearrangements, we report the total synthesi

160 Sigmatropic rearrangements, while rare in biology, offer

161 ry expected for classically pericyclic [3,3] sigmatropic rearrangements.

162 les are favored over the more familiar [3,3]-sigmatropic rearrangements.

163 t center and easily undergoes an endocyclic, sigmatropic ring-closing reaction to form the final 2H-c

164 6pi-electrocyclization (2 --> 3) and [1,5]H-sigmatropic shift (2 --> 4), among which the activation

165 ese adducts can interconvert through a [3,3] sigmatropic shift (Cope rearrangement).

166 ition, 6 thermally rearranges to 7 via a 1,5-sigmatropic shift (DeltaG(267K) = 20.0 +/- 0.5 kcal/mol)

167 on (i) of configuration dominates this [1,3] sigmatropic shift although some retention (r) is also ob

168 of a fluorine atom at C3 also interrupts the sigmatropic shift and changes the rate-determining step

169 ns in which two cycloadducts are linked by a sigmatropic shift have been identified.

170 obvious similarities to the well-known [3,3]-sigmatropic shift of 1,5-hexadiene, i.e., the Cope rearr

171 p-substituents, may arise from 5 by a [1,3]-sigmatropic shift of chlorine proceeding via polar trans

172 pha-ketophosphonates are prepared by a [3,3]-sigmatropic shift of enolphosphonates.

173 n, a 6pi electrocyclic ring closure, a [1,5]-sigmatropic shift of hydrogen, a 6pi electrocyclic ring-

174 ype of electrocyclic reaction known as a 1,5-sigmatropic shift of hydrogen.

175 n electron-rich 7-substituent favors the 1,5-sigmatropic shift reaction.

176 etro-ene type [2pi + 2pi + 2sigma] and [3,3]-sigmatropic shift reactions involving the substituent gr

177 Suprafacial sigmatropic shift reactions of 5-substituted cyclopentad

178 th nucleophile trapping (alkylation) and 1,5-sigmatropic shift reactions.

179 shell processes-concerted cycloadditions and sigmatropic shift rearrangements of cycloadducts.

180 e for an unexpected oxyanion-accelerated 1,2-sigmatropic shift was also found for certain systems, le

181 methodology to a sequence involving a [1,3] sigmatropic shift was feasible with a cyclopropylmethyl

182 C into the first example of an aborted [3,3] sigmatropic shift where the pericyclic "transition state

183 conditions are reported that effect a [3,3]-sigmatropic shift whose two-step process is interrogated

184 compound 8 undergoes a very fast 1,3-lithium sigmatropic shift, and all of the phenyls in the above c

185 hat it functions as a substituent on a [3,3] sigmatropic shift, rather than a nucleophile; thus, the

186 p from the conformation required for the 1,5-sigmatropic shift, then nucleophile trapping occurs.

187 position is therefore favored in the initial sigmatropic shift.

188 om to which it migrates in the result of the sigmatropic shift.

189 [3,3]-Sigmatropic shifts (hetero-Cope rearrangements) of the c

190 Competing [4 + 2] cycloadditions and various sigmatropic shifts are also explored.

191 The [1,3] carbon sigmatropic shifts are not controlled by orbital symmetr

192 details of stereomutations and [1,3] carbon sigmatropic shifts are now being pursued and will in tim

193 experiments revealed that sulfur can undergo sigmatropic shifts around all four sides of the diazetin

194 connection between anionic cyclizations and sigmatropic shifts offers new possibilities for the desi

195 The thermal stereomutations and [1,3] carbon sigmatropic shifts shown by (+)-(1S,2S)-trans-1-(E)-prop

196 Compounds 5 and 8 undergo fast 1,3-Li-sigmatropic shifts that are proposed to take place withi

197 rconversions of various cycloadducts through sigmatropic shifts were also explored.

198 migration occurs through a series of formal sigmatropic shifts.

199 ions can be considered to be "aborted" [2,3]-sigmatropic shifts.

200 effectively with concerted symmetry-allowed sigmatropic steps, and (3) azolium methanide zwitterions

201 mics and the activation barrier of the [3,3]-sigmatropic tautomerism.

202 to functionalized allenes through the [3,3]-sigmatropic transformation of propargyl vinyl ethers.

203 rgies, and electronic characteristics of the sigmatropic transposition compared to those of the unsub