ライフサイエンスコーパス: cycloadduct

1 nsfer of one alkyl group to the intermediate cycloadduct.

2 te a tetrahydropyridinium ion as the initial cycloadduct.

3 e is thermally converted into a [4 + 2]-like cycloadduct.

4 observed Diels-Alder and an unobserved [6+4] cycloadduct.

5 ibromoenone building blocks from the racemic cycloadduct.

6 sure of the intermediate eight-membered-ring cycloadduct.

7 te, followed by direct nucleosidation of the cycloadduct.

8 vinylcyclopropane to produce an intermediate cycloadduct.

9 ference to formation of the expected (4 + 3) cycloadduct.

10 e remaining six stereocenters in the cascade cycloadduct.

11 e remaining six stereocenters in the cascade cycloadduct.

12 oadduct and, more slowly, a rearomatized 2:1 cycloadduct.

13 n giving a preference for hetero-Diels-Alder cycloadducts.

14 do-[4 + 2] (endo-2) and exo-[2 + 2] (anti-3) cycloadducts.

15 ane cleavage of the initially formed [2 + 2] cycloadducts.

16 philes such as enol ethers to afford [4 + 2] cycloadducts.

17 ding to ring-opening of the initially formed cycloadducts.

18 nd readily isolable bridged bicyclic lactone cycloadducts.

19 provide azabicyclo[n.2.1]alkanes as the endo cycloadducts.

20 ions and sigmatropic shift rearrangements of cycloadducts.

21 ndo- and 5-endo-substituted bicyclic lactone cycloadducts.

22 water from the initially formed Diels-Alder cycloadducts.

23 and stereoselective formation of the desired cycloadducts.

24 he second epoxidation efficiently leading to cycloadducts.

25 the chemical versatility of the Diels-Alder cycloadducts.

26 m mixtures of starting materials and [4 + 2] cycloadducts.

27 ic hydrogenation of the intermediate 4-nitro cycloadducts.

28 o the trend in closed-shell repulsion in the cycloadducts.

29 ly in [8pi + 2pi] cycloadditions to give 1,7-cycloadducts.

30 ased metal-binding activity of the phenazine cycloadducts.

31 iodobenzene, affords the lactone and aurone cycloadducts.

32 h 3-substituted furans gave selectively anti cycloadducts.

33 ng access to diverse [2+2], [3+2], and [4+2] cycloadducts.

34 he diene used for the preparation of the key cycloadduct 10 using an acylnitroso-based hetero-Diels-A

35 the functionality present in the rearranged cycloadduct 10.

36 in and lactam functionalities in 1,2-diazine cycloadducts 11 and 15.

37 s were examined for the reaction of N-acetyl cycloadduct (11) and benzyloxyacetaldehyde (10).

38 is is a two-photon product, with the initial cycloadduct (11) ring opening to a cyclooctatriene (12)

39 Acylnitroso Diels-Alder cycloadduct (11, 37, and 45)- and cyclopentenyl acetate

40 nitrogen atom to form the four-membered FLP cycloadduct 15.

41 acts with 1-methoxy-1,3-butadiene to provide cycloadduct 16.

42 1,3-cyclopentadiene forms the diastereomeric cycloadducts 16a,b in a ratio of 3.1:1 (16a:16b).

43 ene in the presence of a Lewis acid produces cycloadducts 16a,b in a ratio of 7:1 (16a:16b), which ap

44 Treatment of cycloadduct 17 with dimethyl(methylthio)sulfonium tetraf

45 reacts with 9,10-dimethylanthracene to give cycloadduct 17, which undergoes retro Diels-Alder dissoc

46 afforded a quantitative yield of the desired cycloadduct 19, which could be easily reduced to the per

47 exadiene to form a mixture of diastereomeric cycloadducts (19 and 20) in a 1.6:1 ratio.

48 (1) and its cis isomer (3) convert slowly to cycloadducts 2 and 4, respectively.

49 However, treatment of cycloadducts 2 with copper(II) in toluene reverses the s

50 Treatment of acylnitroso hetero Diels-Alder cycloadducts 2 with iron(III) or copper(II) in an alcoho

51 Treatment of acylnitroso hetero Diels-Alder cycloadducts 2 with organomagnesium reagents in the pres

52 ewise, there is evidence that two other meta cycloadducts (2 and 3) are also formed with appreciable

53 framework and vicinal quaternary centers in cycloadduct 20 in the key bond-forming step.

54 one derivative 36 was eventually formed from cycloadduct 22 by an acid-induced hydrolysis of 22 to gi

55 The major cycloadduct 22 was used in a formal synthesis of (-)-spi

56 with excellent diastereoselectivity to give cycloadduct 22, which possesses the required stereochemi

57 The cycloadduct 3 is unstable and exists in equilibrium with

58 ) analogue 30b gave the intramolecular 2 + 2 cycloadduct 31b.

59 arene anion radicals, the very same [2 + 2] cycloadducts 3a-3e are formed.

60 The collective data suggest that [2 + 2] cycloadducts 3a-3e arising under Gilman conditions may b

61 clobutane (2 + 2) and cyclohexene-containing cycloadducts (4 + 2).

62 Cycloadduct 41 is then stereospecifically elaborated to

63 nversion of N-benzyl-3-hydroxyoxindole 1o to cycloadducts 4a-4h.

64 0]octane core, are prepared in 14 steps from cycloadduct 6.

65 3-cyclopentadiene to give the diastereomeric cycloadducts 6a,b in a ratio of 1.5:1 (6a:6b).

66 fulvene (2) affords the expected Diels-Alder cycloadduct, 7-(1-methylethylidene)-3,3-bis(trifluoromet

67 ss of hydrogen gas from the initially formed cycloadduct, a tetraenyl intermediate.

68 se dyotropic skeletal rearrangement of these cycloadducts, a reaction also first described by Himbert

69 Chemical manipulation of these cycloadducts affords highly substituted and functionally

70 with N-Boc (37a) and N-methylcarbamate (37b) cycloadducts also gave the cis-1,4-products predominantl

71 In addition to meta cycloadducts analogous to those observed in solution, po

72 d); experimentally, this reaction gives both cycloadduct and copolymer.

73 lenedicarboxylate to give a rearomatized 1:1 cycloadduct and, more slowly, a rearomatized 2:1 cycload

74 oketenes 21 with CO, to form [2+2] and [2+4] cycloadducts and borane adducts, and to cyclize to 1H-di

75 Silicon-substituted cycloadducts and cross-coupled products were also charac

76 Two of the silicon-substituted Diels-Alder cycloadducts and one of the Hiyama cross-coupling produc

77 es metallo-oxy-pi-allyls en route to [2 + 2] cycloadducts and, under Ni catalysis, homoaldol cyclored

78 ing to nearly equal amounts of prox and dist cycloadducts, and (b) the proximal transition state is s

79 pi(dienone)] and [2pi(diene) + 4pi(dienone)] cycloadducts, and the mixture of products obtained varie

80 thylene under ambient conditions affords the cycloadducts Ar(iPr4) Sn(mu2:nu1:n1-C2H4)2Sn Ar(iPr4 (3)

81 arophile), and further derivatization of the cycloadduct are reported.

82 The resulting cycloadducts are cleaved reductively to provide azapolyc

83 The major enantiomers of the cycloadducts are derived from S(N)2-like reactions of th

84 The results support a mechanism in which all cycloadducts are formed from the E isomer of the oxyally

85 al bispericyclic cycloadditions in which two cycloadducts are linked by a sigmatropic shift have been

86 of reaction temperatures, the desired formal cycloadducts are obtained.

87 ddition, the photophysical properties of the cycloadducts are presented.

88 intermediates and several unstable alternate cycloadducts arising from (2 + 2) cycloadditions and het

89 d employing an N-Boc acylnitroso Diels-Alder cycloadduct as the starting material.

90 al ynones gave the corresponding fluorescent cycloadducts as bimane analogues in very high yields.

91 ic aldehydes with alpha-ketols to form [4+2] cycloadducts as single diastereomers.

92 the further functionalization of the [4 + 2] cycloadducts, as illustrated by the preparation of 20 va

93 tion pathways leading to [4 + 2] and [2 + 2] cycloadducts, as well as a novel [6 + 4] ene product.

94 imine)2Cu(+) complexes for the prox and dist cycloadducts, assessed by ESI-MS, is marginally correlat

95 the thermodynamically preferred [4 + 2]-like cycloadduct at a temperature higher than 300 K.

96 The kinetically favored [2 + 2]-like cycloadduct at low temperature is thermally converted in

97 hetically and biologically important [4 + 2] cycloadducts at room temperature.

98 In addition, cycloadducts bearing a strained cyclobutanone moiety wer

99 dinophanes, such as 5m and 29m, and an ortho cycloadduct (benzannulation product), such as 29o.

100 ormation of the expected [2 + 2] diazetidine cycloadducts but also to unexpected 2:1 adducts of MeTAD

101 2 and 14 with DMAD lead to the corresponding cycloadducts, but the subsequent aromatization is compli

102 solation of the corresponding nitrosobenzene cycloadduct by means of catalytic amounts of CuCl.

103 tion of an 8-oxabicyclo[3.2.1]oct-6-en-3-one cycloadduct by means of the Moriarty method.

104 yrazinium-3-olate and MMA yielding a [3 + 2] cycloadduct (CA); (ii) a skeletal rearrangement, which c

105 iene and 2,3-dimethyl-1,3-butadiene (several cycloadducts characterized by X-ray crystallography).

106 ed out in cyclohexene but the carbene-alkene cycloadduct could be detected, albeit in low yield, in t

107 ding both Diels-Alder and hetero-Diels-Alder cycloadducts could be located.

108 the exception of 45 and 46, the oxa-bridged cycloadducts could not be isolated but immediately under

109 eover, the strategic manipulation of nitrone cycloadducts demonstrates the utility of this methodolog

110 The cycloadduct derived from reaction of pyrazinone and male

111 te, were found to afford oxabicyclic dipolar cycloadducts derived by the trapping of a carbonyl ylide

112 The cycloadducts derived from cyclic 2-azaallyllithium speci

113 of azides to acylnitroso hetero-Diels-Alder cycloadducts derived from cyclopentadiene affords exo-tr

114 presence of several dienophiles gave [4 + 2]-cycloadducts derived from the Diels-Alder reaction of a

115 the corresponding Diels-Alder mono- and bis-cycloadducts derived from the presumed aryne intermediat

116 henylketene affords both [4 + 2] and [2 + 2] cycloadducts directly.

117 regioselective, typically producing a single cycloadduct, ensuring their synthetic utility, but both

118 An in situ ring opening reaction of exo-cycloadduct ethyl exo-2-(N,N-diethylcarbamoyloxy)-3,3-di

119 These phenazine cycloadducts exhibit a selective affinity for binding si

120 These cycloadducts exhibited a distinct response to Cu(2+), Ni

121 ropy, DeltaStotal, considerations favor endo cycloadducts for both dienophiles with DHP, while total

122 favor endo cycloadducts for styrene and exo cycloadducts for MVK.

123 l energy considerations, DeltaEo, favor endo cycloadducts for styrene and exo cycloadducts for MVK.

124 o detect fumarate via fluorescent pyrazoline cycloadduct formation.

125 ring generally increased both the amount of cycloadduct formed and the rate of cycloaddition relativ

126 ydroxy group as an active participant in the cycloadduct fragmentation process.

127 Furthermore, the utility of these cycloadducts has been demonstrated by an NBS-MeOH mediat

128 Structural studies of the cycloadducts have allowed for quantification of the defo

129 tivated cumulene double bond, forming distal cycloadducts (i.e., 57) in the case of alpha-tethered al

130 amounts of chiral amine and acid to afford a cycloadduct in 64% yield as a single diastereomer with a

131 om an acylnitroso-derived hetero Diels-Alder cycloadduct in fewer than nine steps.

132 adiene gives rise to a 7-oxa-1-azanorbornane cycloadduct in high yield.

133 efsky diene to various aryl imines to afford cycloadducts in > or =89% ee and > or =85% isolated yiel

134 -100 degrees C directly provided the [3 + 2] cycloadducts in excellent yields (60-88%) under mild the

135 room temperature to deliver the Diels-Alder cycloadducts in good to excellent yield.

136 the presence of triethylamine afforded (4+3) cycloadducts in good to excellent yields.

137 cycloadditions, provide diverse and complex cycloadducts in good yields.

138 h various dienes to afford the corresponding cycloadducts in high yields (90-98%).

139 henylethylurea) 3 (same conditions) gave NDA cycloadducts in high yields (97-99%) with no ene product

140 nditions, thus only providing the aromatized cycloadducts in modest yields.

141 th other dienophiles, providing the expected cycloadducts in most cases, although an abnormal adduct

142 r variants provide either [1 + 2] or [3 + 2] cycloadducts in reactions that depend on the reaction co

143 ione 9, using chiral rhodium catalysts, gave cycloadducts in up to 51% ee.

144 lder reaction, which proceeded to afford the cycloadducts in up to 95% ee.

145 yamide protecting groups with no harm to the cycloadduct, in contrast with the unreacted diene that i

146 h mild thermal activation providing a single cycloadduct, in most cases the initial, nonaromatic addu

147 Cycloadducts incorporating suitable functional groups ca

148 ar distributions of transannular Diels-Alder cycloadducts, indicating that the C(6)-Br and C(21)-ster

149 Ensuing transformation of these cycloadducts into functionalized piperidines establishes

150 ure validation was achieved by conversion of cycloadducts into known [2.2.2]diazabicyclic compounds o

151 A unique intramolecular ortho cycloadduct is also formed from 1 but only within a narr

152 Ring opening of the resulting cycloadduct is followed by deprotonation to furnish a re

153 escribe enantioselective syntheses of aglain cycloadducts leading to the first total syntheses and ab

154 contrast was confirmed by X-ray analysis of cycloadducts not susceptible to epimerization.

155 lidines have been synthesized from the major cycloadducts obtained by the 1,3-dipolar cycloaddition o

156 sal of the stereochemistry in the respective cycloadducts obtained using C(1)- and C(2)-symmetric ami

157 An intramolecular hetero-Diels-Alder cycloadduct of an acyl nitroso compound and a 9,10-dimet

158 igned and easily prepared from a Diels-Alder cycloadduct of an enantiomerically pure anthracene with

159 col is described for the conversion of [4+2] cycloadducts of 2-(trialkylsilyloxy)-1,3-dienes to 1,6(2

160 Fifteen substituted maleimide cycloadducts of anthracene derivatives were synthesized

161 ngements and ring expansions of azapentalene cycloadducts of imidazolo- and triazolodicyanomethanide

162 [reaction: see text] Acyl nitroso cycloadducts of the alkaloid thebaine undergo an unexpec

163 has been examined and the boron substituted cycloadducts of those cycloaddition reactions have been

164 d (ii) regioselectivity leading to a [2 + 2] cycloadduct or an ene product when (1)O(2) reacts with a

165 ation of a proton can give the usual Nazarov cycloadduct, or ring contraction can give an alternative

166 enerated by nitrogen-assisted opening of the cycloadduct oxido bridge, with a modification that permi

167 the Diels-Alder step is also high, with endo cycloadducts produced as the exclusive products of the r

168 e superoxide species reduces the Diels-Alder cycloadduct radical cation to the final product and refo

169 owed by reductive removal of sulfur from the cycloadduct resulted in the formation of (+/-)-alloyohim

170 This cycloadduct ring opening methodology was applied to the

171 of 2(Ph) with 2-substituted furans gave syn cycloadducts selectively, while cycloadditions with 3-su

172 The resultant efficiently formed dienone cycloadducts serve as substrates for subsequent Nazarov

173 es with a highly efficient conversion to the cycloadduct, showing no significant wavelength dependenc

174 Upon reduction and hydrolysis of the cycloadducts, substituted cyclohexenones were obtained w

175 Reductive desulfurization of these cycloadducts takes place under mild conditions and in ex

176 product and improves the yield of the formal cycloadduct, tetrahydroisoquinolonic carboxylate 10.

177 Compound 4 is an intramolecular meta cycloadduct that is generated in the gas phase with suff

178 ation of a series of cyclohexadienyl-benzene cycloadducts that are oxidized to the corresponding biar

179 ith 1,3-dienes to form highly functionalized cycloadducts that can be directly transformed into allyl

180 eactions to afford mixtures of regioisomeric cycloadducts that map onto the alternative carbocyclic f

181 This investigation uncovers regioisomeric cycloadducts that were not found in previous studies inv

182 F3 with Cp 2 yields the expected exo [4 + 2] cycloadduct, the reactions of these FHCs yield Michael a

183 ition, further manipulation of the resulting cycloadduct through the remaining double bond is possibl

184 Interconversions of various cycloadducts through sigmatropic shifts were also explor

185 The addition of N-acetyl cycloadduct to aliphatic aldehydes afforded products in

186 e NMR experiment that converted the unstable cycloadduct to product imine.

187 Exposure of the resulting cycloadducts to additional acetic anhydride leads to rin

188 rangement metathesis of Himbert arene/allene cycloadducts to form fused polycylic lactams led to a mo

189 hynylated phenazines and their bis-triazolyl cycloadducts to serve as metal ion sensors.

190 l, to facilitate conversion of the cis-fused cycloadducts to the trans-fused series.

191 rates, there is a tendency for these initial cycloadducts to undergo aromatization, ene reaction, and

192 olefin tether to provide tetrahydroquinoline cycloadducts under mild acidic conditions.

193 The resulting cycloadduct undergoes loss of COS, and further reduction

194 The initially formed [4+2]-cycloadduct undergoes nitrogen-assisted ring opening fol

195 The initially formed [4 + 2]-cycloadduct undergoes nitrogen-assisted ring opening fol

196 The initially formed [4+2]-cycloadduct undergoes nitrogen-assisted ring opening fol

197 The resulting oxa-bridge cycloadducts underwent a subsequent 1,2-methylthio shift

198 Furthermore, some endo-cycloadducts underwent isomerization of the carbons vici

199 Furthermore, these cycloadducts underwent retro-1,3-dipolar cycloaddition y

200 the four possible regio- and stereoisomeric cycloadducts using density functional theory (B3LYP/6-31

201 Differentiation of carbonyl groups in the cycloadduct was made by an intramolecular reaction with

202 In fact, the cycloadduct was subsequently converted to a common inter

203 The resulting cycloadduct was used for the stereocontrolled installati

204 A) chains anchored by a maleimide-anthracene cycloadduct were synthesized to demonstrate mechanochemi

205 The isolated cycloadducts were all thermally labile and quantitativel

206 These cycloadducts were found to be useful as starting materia

207 NDA cycloadducts were not obtained from other hydroxamic aci

208 cis-disubstituted dienophiles, the resulting cycloadducts were obtained as single diastereomers in go

209 were employed as catalysts, the Diels-Alder cycloadducts were obtained with much lower enantioselect

210 and then the silicon-substituted Diels-Alder cycloadducts were used in Hiyama cross-coupling reaction

211 lic transition state lead to the Diels-Alder cycloadducts, whereas a smaller number of downhill paths

212 aining tether yield successfully the desired cycloadducts, whereas the corresponding substrates witho

213 almost exclusively to the corresponding endo cycloadduct, which is in good agreement with previous ex

214 ted with trimethylaluminum to give a [2 + 2]-cycloadduct, which underwent retroaldol fission to produ

215 eduction of the ketone carbonyl group of the cycloadducts, which possess a basic structure of bicycli

216 phenylmaleimide afforded exclusively the exo cycloadduct, while high endo stereoselectivity was obser

217 s that the lowest energy path to many of the cycloadducts will involve diradical intermediates, where

218 e carbene could also be trapped as a [2 + 1] cycloadduct with 2,3-dimethyl-2-butene.

219 Treatment of the cycloadduct with 5% Na/Hg results in reductive nitrogen-

220 Treatment of this cycloadduct with excess MeMgCl resulted in the formation

221 d by the diol or ketol reactant releases the cycloadduct with regeneration of ruthenium(0) and the re

222 The cycloadducts with a 4-(dimethylamino)phenyl group on the

223 reductive cleavage of nitrosobenzene-derived cycloadducts with appropriately protected 1,2-dihydropyr

224 ors to provide the corresponding pyrrolidine cycloadducts with excellent yields and selectivities.

225 sterically encumbered allenes afford higher cycloadduct yields, and such effects are also observed i