ライフサイエンスコーパス: cycloadduct

1 e remaining six stereocenters in the cascade cycloadduct.

2 e remaining six stereocenters in the cascade cycloadduct.

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

4 te a tetrahydropyridinium ion as the initial cycloadduct.

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

6 ibromoenone building blocks from the racemic cycloadduct.

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

8 he ability to "mask" itself as an air-stable cycloadduct.

9 e for the degree of stereoselectivity of the cycloadduct.

10 nsfer of one alkyl group to the intermediate cycloadduct.

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

12 te, followed by direct nucleosidation of the cycloadduct.

13 vinylcyclopropane to produce an intermediate cycloadduct.

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

15 d to determine the structure of the two mono-cycloadducts.

16 ased metal-binding activity of the phenazine cycloadducts.

17 iodobenzene, affords the lactone and aurone cycloadducts.

18 mote the formation of unusual diastereomeric cycloadducts.

19 h 3-substituted furans gave selectively anti cycloadducts.

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

21 r capability of forming structurally complex cycloadducts.

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

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

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

25 h acrolein to form enantiomerically enriched cycloadducts.

26 and (2+2) reactions to provide a variety of cycloadducts.

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

28 nd readily isolable bridged bicyclic lactone cycloadducts.

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

30 ions and sigmatropic shift rearrangements of cycloadducts.

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

32 water from the initially formed Diels-Alder cycloadducts.

33 n with a different dienophile to form 2-fold cycloadducts.

34 and stereoselective formation of the desired cycloadducts.

35 he second epoxidation efficiently leading to cycloadducts.

36 the chemical versatility of the Diels-Alder cycloadducts.

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

38 ate that some chemistry is possible with the cycloadducts.

39 e present between nucleobases and pyridazine cycloadducts.

40 e evolution of trajectories to give the four cycloadducts.

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

42 ic hydrogenation of the intermediate 4-nitro cycloadducts.

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

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

45 significant factors impacting conversion to cycloadduct: (1) the silyl transfer group has a substant

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

47 the functionality present in the rearranged cycloadduct 10.

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

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

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

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

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

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

54 1,3-cyclopentadiene forms the diastereomeric cycloadducts 16a,b in a ratio of 3.1:1 (16a:16b).

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

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

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

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

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

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

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

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

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

64 and intramolecular hetero Diels-Alder (IHDA) cycloadducts 2.

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

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

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

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

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

70 The cycloadduct 3 is unstable and exists in equilibrium with

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

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

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

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

75 Cycloadduct 41 is then stereospecifically elaborated to

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

77 0]octane core, are prepared in 14 steps from cycloadduct 6.

78 3-cyclopentadiene to give the diastereomeric cycloadducts 6a,b in a ratio of 1.5:1 (6a:6b).

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

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

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

82 e that leads to favored formation of (2 + 2) cycloadducts across the keteniminium C-C bond.

83 Chemical manipulation of these cycloadducts affords highly substituted and functionally

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

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

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

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

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

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

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

91 ontaining 1,2-pyridazine inverse Diels-Alder cycloadducts and their precursors were hybridized to sho

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

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

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

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

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

97 The resulting cycloadducts are cleaved reductively to provide azapolyc

98 ty of further transformations of the initial cycloadducts are demonstrated to highlight the versatili

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

100 Linear and angular [2 + 3] cycloadducts are formed as major products.

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

102 The [4+2] cycloadducts are generated as single diastereomers with

103 different cycloreversion rates of the formed cycloadducts are leveraged to achieve in situ multi-topo

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

105 ethyl propiolate, competing 2:1 ylide/alkyne cycloadducts are observed.

106 been applied and the corresponding [12 + 2] cycloadducts are obtained with excellent stereoselectivi

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

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

109 ophile chemistry, and the corresponding para-cycloadducts are treated with oxygen nucleophiles via fo

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

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

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

113 ed, and cyclic alkenes reacted to afford the cycloadducts as single constitutional isomers in 48-80%

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

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

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

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

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

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

120 C-2 reacted efficiently, giving the [4 + 2] cycloadducts at room temperature with high yields.

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

122 In addition, cycloadducts bearing a strained cyclobutanone moiety wer

123 ehydration and aromatization of the obtained cycloadducts bearing the resolved P-stereogenic phosphin

124 Despite the [6 + 4]-cycloadduct being thermodynamically preferred, [4 + 2]-c

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

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

127 2 and 14 with DMAD lead to the corresponding cycloadducts, but the subsequent aromatization is compli

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

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

130 rt the analysis of coumarin and styrylpyrene cycloadducts by cyclic ion-mobility tandem mass spectrom

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

132 hetero-[5+2] cycloaddition reaction and the cycloadducts can be readily transformed into the core sk

133 ersion process, the dissociation rate of the cycloadducts can be tuned in a facile manner, thus allow

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

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

136 electrophilic alkenes, (3 + 2) gamma-lactam cycloadducts could be formed with a high level of diaste

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

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

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

140 The cycloadduct derived from reaction of pyrazinone and male

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

142 The cycloadducts derived from cyclic 2-azaallyllithium speci

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

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

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

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

147 cutive rearrangements, rendering these ortho cycloadducts elusive.

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

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

150 olefins and afforded appreciable quantity of cycloadduct even at room temperature; and (3) the proxim

151 These phenazine cycloadducts exhibit a selective affinity for binding si

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

153 ate that undergoes cyclization to afford the cycloadduct, followed by eliminative catalyst release.

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

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

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

157 can be obtained in good yields from the pure cycloadducts, form with high regio- and stereoselectivit

158 o detect fumarate via fluorescent pyrazoline cycloadduct formation.

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

160 enerate stable triazolines; in contrast, the cycloadducts formed by heating analogous azidoalkyl viny

161 ne-pot method utilizes arene-arenophile para-cycloadducts, formed via visible-light-mediated [4+2]-ph

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

163 ition states that can lead to either type of cycloadduct from one transition state.

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

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

166 2) single bond in some tetrahydronaphthalene cycloadducts have also been revealed.

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

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

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

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

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

172 eaction opening the access to functionalized cycloadducts in a diastereoselective manner by employing

173 -100 degrees C directly provided the [3 + 2] cycloadducts in excellent yields (60-88%) under mild the

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

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

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

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

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

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

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

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

182 can be captured as corresponding 1,3-dipolar cycloadducts in the presence of DHPO.

183 However, only the two cycloadducts in the product pool that incorporate both r

184 spect of these studies is the utility of the cycloadducts in the synthesis of complex natural product

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

186 pe was explored, affording the corresponding cycloadducts in up to 80% yield, 15:1 dr, and 94% ee.

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

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

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

190 Cycloadducts incorporating suitable functional groups ca

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

192 ting stepwise exo-cycloaddition leading to a cycloadduct initially in a boat-conformation, subsequent

193 stereomeric mixture of 1,2-dihydropyridazine cycloadduct intermediates was isolated, characterized, a

194 Ensuing transformation of these cycloadducts into functionalized piperidines establishes

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

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

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

198 The 2 + 2 cycloadduct is formed by an anti-transition state follow

199 t under kinetic control, but the Diels-Alder cycloadduct is formed under thermodynamic control.

200 r head-to-tail conformation of the resulting cycloadducts is often challenging by conventional spectr

201 r head-to-head and head-to-tail styrylpyrene cycloadduct isomers, ion mobility enabled CID-MS/MS was

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

203 Alkyl lithium-promoted fragmentation of the cycloadducts led to the cyclic derivatives after 1,4- or

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

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

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

207 of dead-end prenylated flavin mononucleotide cycloadducts occurs with distinct propenoic and propioli

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

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

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

211 Fifteen substituted maleimide cycloadducts of anthracene derivatives were synthesized

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

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

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

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

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

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

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

219 These cycloadducts provide a convenient entry into the 3-azabi

220 Double dehydration of the diol-containing cycloadduct provides an achiral enone, which upon asymme

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

222 s produces diastereodivergently exo- or endo-cycloadducts, respectively.

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

224 dihydrooxazole nitrogen, Ghosez found major cycloadducts resulting from an attack of ketene carbonyl

225 This cycloadduct ring opening methodology was applied to the

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

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

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

229 des confirmed preferential formation of endo cycloadduct stereochemistry, imparting significant struc

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

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

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

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

234 Alder cycloadditions to generate isopyridine cycloadducts that are converted to pyridines upon furthe

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

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

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

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

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

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

241 Interconversions of various cycloadducts through sigmatropic shifts were also explor

242 The triazoline cycloadduct thus formed spontaneously decomposes via a r

243 cient leaving group within the corresponding cycloadduct, thus enabling unprecedented ring-contractin

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

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

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

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

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

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

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

251 Cathodic reduction of the cycloadduct triggers a radical fragmentation pathway del

252 afluoroethylene and butadiene form the 2 + 2 cycloadduct under kinetic control, but the Diels-Alder c

253 azepinone products over a potential (3 + 2)-cycloadduct under mild reaction conditions allows for th

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

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

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

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

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

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

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

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

262 functionalize an alkene group in the [4 + 2] cycloadduct using a Mukaiyama hydration and a subsequent

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

264 oethylene (TFE) yields exclusively a [2 + 2] cycloadduct via a stepwise diradical mechanism.

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

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

267 The resulting cycloadduct was used for the stereocontrolled installati

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

269 The isolated cycloadducts were all thermally labile and quantitativel

270 Cycloadducts were constructed from ethynylated and vinyl

271 These cycloadducts were found to be useful as starting materia

272 NDA cycloadducts were not obtained from other hydroxamic aci

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

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

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

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

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

278 veal that the pathway leading to the [8 + 2] cycloadduct, which involves an initial nucleophilic addi

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

280 gioselective formation of a single transient cycloadduct, which undergoes chemoselective fragmentatio

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

282 Intriguingly, these complex cycloadducts, which can be obtained in good yields from

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

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

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

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

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

288 alyzed allylic substitution of the resulting cycloadduct with a Grignard reagent.

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

290 tereogenic centers, and provided a tricyclic cycloadduct with high diastereoselectivity and isolated

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

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

293 red by a simple phenoxy linker and furnishes cycloadducts with a prominent structural motif found in

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

295 l-substituted vinylphosphine oxides leads to cycloadducts with complete regioselectivity and with cis

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

297 act in a stereoconvergent fashion, providing cycloadducts with the same sense of absolute stereochemi

298 s ([4 + 6]-, [2 + 8]-, [8 + 2]-, and [6 + 4]-cycloadducts) without any intervening minima has been de

299 reaction that can negatively impact [5 + 2] cycloadduct yields and efficiency.

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