Rhodium-catalyzed Enantioselective [2 + 2 + 2] Cycloaddition of Tosylamide-linked 5-Allenal and 5-Allenone with Internal Alkynes

Sakashita, Kazuki; Masutomi, Koji; Noguchi, Keiichi; Tanaka, Ken

doi:10.1246/cl.140448

Cited by 13 publications

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“…Recently,o ur research group reported the rhodiumcatalyzed enantioselective [2+ +2+ +2] cycloaddition of tosylamide-linked 5-allenals and 5-allenones with internal alkynes. [9] In this study,w ef ound that the reaction of the tosylamide-linked 5-allenone with di-tert-butylacetylenedicarboxylate in the presence of ac ationic rhodium(I)/binap catalyst does not afford the expected [2+ +2+ +2] cycloaddition product, but instead delivers an unexpected cross-cyclotrimerization product, 3,6-dialkylidenecyclohex-1-ene derivative, in good yield (Scheme 2).…”

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confidence: 92%

Rhodium‐Catalyzed Cross‐Cyclotrimerization and Dimerization of Allenes with Alkynes

2016

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confidence: 92%

Rhodium‐Catalyzed Cross‐Cyclotrimerization and Dimerization of Allenes with Alkynes

2016

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“…Recently, our research group reported the rhodium‐catalyzed enantioselective [2+2+2] cycloaddition of tosylamide‐linked 5‐allenals and 5‐allenones with internal alkynes . In this study, we found that the reaction of the tosylamide‐linked 5‐allenone with di‐ tert ‐butylacetylenedicarboxylate in the presence of a cationic rhodium(I)/binap catalyst does not afford the expected [2+2+2] cycloaddition product, but instead delivers an unexpected cross‐cyclotrimerization product, 3,6‐dialkylidenecyclohex‐1‐ene derivative, in good yield (Scheme ).…”

Section: Methodsmentioning

confidence: 80%

Rhodium‐Catalyzed Cross‐Cyclotrimerization and Dimerization of Allenes with Alkynes

2016

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It has been established that ac ationic rhodium(I)/ binap complex catalyzest he cross-cyclotrimerization of two molecules of am onosubstituted allene with one molecule of af unctionalized alkyne to give 3,6-dialkylidenecyclohex-1-enes.I nc ontrast, the reactions involving di-or trisubstituted allenes and/or unfunctionalized alkynes afforded cross-dimerization products,substituted dendralenes,through b-hydrogen elimination from the corresponding rhodacycles.Transition-metal-catalyzed intermolecular cross-cyclotrimerization and cross-dimerization reactions of alkynes with alkenes are efficient and atom-economical methods for the synthesis of substituted six-membered carbocycles and dienes, respectively.[1] In contrast, similar transformations using allenes in place of alkenes have been reported in al imited number of examples.[2] As examples of the cross-cyclotrimerization of alkynes with allenes, [3][4][5] the nickel-catalyzed reactions of one molecule of am onosubstituted allene with two molecules of an electron-deficient internal alkyne followed by aromatization through olefin isomerization, which affords the corresponding pentasubstituted benzenes, has been reported (Scheme 1a).[3a] However,t he usable alkynes are limited to electron-deficient alkynoates,a nd electron-rich alkynes cannot be employed.[3a] Furthermore, as elective and general method for the cross-cyclotrimerization of two molecules of an allene and one molecule of an alkyne has not been reported to date. [5] As examples of the cross-dimerization of allenes with alkynes,t hermal reactions giving substituted dendralenes have been reported (Scheme 1b). [6][7][8] However,t he usable alkynes are limited to electron-deficient dimethyl acetylenedicarboxylate and (trifluoromethyl)acetylene.[6] Herein, we disclose the crosscyclotrimerization of two molecules of am onosubstituted allene with functionalized alkynes,a nd cross-dimerization of di-or trisubstituted allenes with both functionalized and unfunctionalized alkynes.Recently,o ur research group reported the rhodiumcatalyzed enantioselective [2+ +2+ +2] cycloaddition of tosylamide-linked 5-allenals and 5-allenones with internal alkynes. [9] In this study,w ef ound that the reaction of the tosylamide-linked 5-allenone with di-tert-butylacetylenedicarboxylate in the presence of ac ationic rhodium(I)/binap catalyst does not afford the expected [2+ +2+ +2] cycloaddition product, but instead delivers an unexpected cross-cyclotrimerization product, 3,6-dialkylidenecyclohex-1-ene derivative, in good yield (Scheme 2).Thus,w ee xamined the reaction of the monosubstituted allene 1a with di-tert-butylacetylenedicarboxylate (2a)inthe presence of the same rhodium catalyst (Table 1). Pleasingly, the cross-cyclotrimerization proceeded at room temperature to give the corresponding 3,6-dialkylidenecyclohex-1-ene 3aa,a lthough the regioisomer 4aa was generated as aminor product (entry 1). Theeffect of biaryl bis(phosphine) ligands was then examined (entries 1-5). Increasing the dihedral angle of ligands impro...

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“…[92] Other reports have described completely intramolecular or partially intramolecular [2+ +2+ +2] cycloadditions involving allene anda ldehydem oieties to afford pyrand erivatives. [93] In particular, [2+ +2+ +2] cycloadditions of 1,7-enynes with carbonyl speciesr esulted in the formationo fo xacyclic cycloadducts from an interception of gold-containing cyclobutenium intermediates with carbonyl species (Scheme 53). [94] Another intermolecular gold(I)-catalyzed reactiono ft erminal alkynes with ketones containing ar emote alkene led to 8-oxabicyclo[3.2.1]oct-3-enes by a[ 2 + +2+ +2] cycloaddition process catalyzed by ac ationic gold complex.…”

Section: Gold Catalysismentioning

confidence: 99%

Alkenes in [2+2+2] Cycloadditions

Domı́nguez

Pérez‐Castells

2016

Chemistry A European J

125

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Participation of alkenes and allenes in [2+2+2] cycloaddition reactions has attracted much attention recently. This version of the well-established alkyne cyclotrimerization renders interesting products, such as cyclohexadienes and other polycycles, through cascade processes. Many mechanistic variations are observed when using certain metal complexes as catalysts. The frequent generation of stereogenic centers has prompted the development of efficient asymmetric versions. This Minireview summarizes the efforts reported to date on the use of double bonds as partners in [2+2+2] cyclotrimerizations.

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Rhodium-catalyzed Enantioselective [2 + 2 + 2] Cycloaddition of Tosylamide-linked 5-Allenal and 5-Allenone with Internal Alkynes

Abstract: It has been established that a cationic rhodium(I)–BINAP complex catalyzes the enantioselective [2 + 2 + 2] cycloaddition of a tosylamide-linked 5-allenal and 5-allenone with internal alkynes, leading to bicyclic oxygen heterocycles.

Cited by 13 publications

References 31 publications

Rhodium‐Catalyzed Cross‐Cyclotrimerization and Dimerization of Allenes with Alkynes

Rhodium‐Catalyzed Cross‐Cyclotrimerization and Dimerization of Allenes with Alkynes

Rhodium‐Catalyzed Cross‐Cyclotrimerization and Dimerization of Allenes with Alkynes

Alkenes in [2+2+2] Cycloadditions

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