Chemistry of bicyclo[3.1.0]hex-1-enes contrasted with that of 2-alkylidenecyclopentane-1,3-diyls

Rule, Mark; Salinaro, Richard F.; Pratt, D. R.; Berson, Jerome A.

doi:10.1021/ja00372a019

Cited by 30 publications

(17 citation statements)

References 1 publication

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“…They found that the mode of dimerization depends on the reaction temperature as well as structural features of bicyclo[3.1.0]hex-1-enes. 5 At -78 °C, reaction of gem-dibromide 31 37 with MeLi in ether solvent generates hydrocarbon 4 and 38, which is similar to Köbrich's result (Scheme 12). The major product 4 is the consequence of a [+] dimerization of bicyclo[3.1.0]hex-1-ene 3, whereas the minor product 38 is the result of a [+] dimerization.…”

Section: Dimerizationsupporting

confidence: 76%

“…In the early reports of Köbrich 2 and Berson, 5 both vinyl halides and gem-dihalides 8 could be used as precursors for alkylidene carbene 9 (Scheme 4). 6 Deprotonation of vinyl halides or metalation of gem-dihalides followed by -elimina-tion of lithium halide leads to alkylidene carbene intermediate 9, which, after reacting with a tethered alkene, generates bicyclo[3.1.0]hex-1-ene 10.…”

Section: Approaches To Form Bicyclo[310]hex-1enesmentioning

confidence: 99%

“…They found that the mode of dimerization depends on the reaction temperature as well as structural features of bicyclo[3.1.0]hex-1-enes. 5 At -78 °C, reaction of gem-dibromide 31 At higher temperature (0 °C), metalation of bromide 37 generates a small amount of a [+] dimer along with a complex mixture of hydrocarbons 40a-d (Scheme 13). 5 Through an alternative route, the structure of compound 40a was confirmed as a symmetrical dimer of trimethylenemethane (TMM) diradical.…”

Section: Dimerizationmentioning

confidence: 99%

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Strain-Induced Transformations of Bicyclo[3.1.0]hex-1-enes

Ghorai¹,

Lee²

2021

Synthesis

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Bicyclo[3.1.0]hex-1-ene is a highly strained bicyclic intermediate that generates trimethylenemethane (TMM) diradical through breaking the C–C bond of its methylene cyclopropane moiety. The reactivity of bicyclo[3.1.0]hex-1-enes and trimethylenemethane (TMM) diradicals depend on the reaction temperature and substitution patterns. This short review covers various strain-induced transformations of bicyclo[3.1.0]hex-1-enes and their formal [3+2] cycloadditions through TMM diradicals and presents synthetic applications to natural products containing triquinane and tropone structures.1 Introduction2 Early Reports on Bicyclo[3.1.0]hex-1-enes3 Approaches to Form Bicyclo[3.1.0]hex-1-enes4 Structure and Reactivity of Bicyclo[3.1.0]hex-1-enes4.1 Isomerization4.2 Dimerization4.3 [3+2] Cycloaddition4.4 [4+2] Cycloaddition5 Synthetic Applications to Natural Products6 Summary and Outlook

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Section: Dimerizationsupporting

confidence: 76%

Section: Approaches To Form Bicyclo[310]hex-1enesmentioning

confidence: 99%

“…They found that the mode of dimerization depends on the reaction temperature as well as structural features of bicyclo[3.1.0]hex-1-enes. 5 At -78 °C, reaction of gem-dibromide 31 At higher temperature (0 °C), metalation of bromide 37 generates a small amount of a [+] dimer along with a complex mixture of hydrocarbons 40a-d (Scheme 13). 5 Through an alternative route, the structure of compound 40a was confirmed as a symmetrical dimer of trimethylenemethane (TMM) diradical.…”

Section: Dimerizationmentioning

confidence: 99%

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Strain-Induced Transformations of Bicyclo[3.1.0]hex-1-enes

Ghorai¹,

Lee²

2021

Synthesis

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“…In addition this substrate circumvents isomerization of 13 into a triazole since there is no C(4) hydrogen to tautomerize, and any cyclization of the diyl 15a into the alkylideneaziridine-containing species 16 is likely to be thwarted by the significant energetic cost of forming a bicyclic product bearing a trans alkene within a six-membered ring. 9 Thus, we set out to test the premise that 1-azido-3,4,6-heptadienes 1 can serve as effective precursors of the ATMM diyl 15. A priori, it was unclear if the desired regiochemistry of bond formation, C-C as per 15bf2, would be favored over C-N bond formation as per 15cf17.…”

Section: Introductionmentioning

confidence: 99%

Allenyl Azide Cycloaddition Chemistry: Exploration of the Scope and Mechanism of Cyclopentennelated Dihydropyrrole Synthesis through Azatrimethylenemethane Intermediates

et al. 2008

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Detailed studies of the thermal conversion of 1-azidohepta-3,4,6-trienes into cyclopentennelated dihydropyrroles are presented. High levels of diastereoselectivity and regioselectivity are documented. A mechanistic proposal that accounts for all of the diverse results is developed through the use of density functional calculations. These calculations provide support for the intervention of unexpected mechanistic subtleties, such as the planarity of an azatrimethylenemethane diyl intermediate and an apparent Woodward-Hoffmann-type electrocyclization of a five-atom diyl array.

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“…5 Herein we like to report a new and facile synthetic methodology for the stereoselective construction of various 1-acetyl-2-aminomethylcyclopropanes. During the course of our synthetic program utilizing methylenecyclopropane ring system with high strain energy, 6 we studied reaction of the anion of 1 7 with phenyl(propynyl)iodonium triflate (2) with an anticipation of obtaining an azatriquinane compound (3). Instead, we obtained azabicyclo[3.1.0]hexane compound (4) (Scheme 1).…”

mentioning

confidence: 99%

A Stereoselective Synthesis of 1-Acetyl-2-aminomethylcyclopropanes from Allylsulfonamides and Phenyl(alkynyl)iodonium Salts

Lee¹,

Lee²

2001

Synlett

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A versatile and stereoselective synthesis of 1-acetyl-2-aminomethyl cyclopropanes from the reaction of anions of tosylallylamines and phenyl(propynyl)iodonium salt was developed.Peptidomimetics play an important role in understanding enzyme-substrate and receptor-ligand interaction as well as in developing non-peptidic drugs in medicinal chemistry. 1 The most popular form of peptidomimetics is peptide bond isostere 2 that converts peptides into nonpeptides effectively without losing structural integrity of the peptide bonds. Among many peptide isosteres, cyclopropane ring offers sites of appendages for extra binding sites as well as conformational rigidity with defined stereochemistry. 3 Though there are many reports of cyclopropane-peptideisosteres and synthetic methodologies for functionalized cyclopropane rings, 4 stereoselective construction of cyclopropane ring system has been difficult and lengthy in synthesis. 5Herein we like to report a new and facile synthetic methodology for the stereoselective construction of various 1-acetyl-2-aminomethylcyclopropanes. During the course of our synthetic program utilizing methylenecyclopropane ring system with high strain energy, 6 we studied reaction of the anion of 1 7 with phenyl(propynyl)iodonium triflate (2) with an anticipation of obtaining an azatriquinane compound (3). Instead, we obtained azabicyclo[3.1.0]hexane compound (4) (Scheme 1).The structure of 4 was determined through spectroscopic analysis 8 and confirmed by comparison to the earlier report of similar reaction by Feldman. 9 In his report, a plausible mechanism for the formation of a methylene compound from the alkylidene cyclopropane was proposed. While examining the general applicability of this reaction to the synthesis of natural products, 10 we found out that methylene azabicyclo[3.1.0]system was not stable under acidic condition of silica-gel chromatography and slowly decomposed at room temperature even in the pure state. Unstable nature of related methylene azabicyclo[3.1.0] system was reported by Baird. 11 He observed that methylene azabicyclo[3.1.0] system underwent hydration reaction to form hemiaminals under acidic environment and eventually decomposed to unidentifiable products. There also was a report that even methylenepyrrolidines were not stable during purification. 12 Since our enamines were sulfonamides, they might more prone to hydrolysis reaction and thus treatment with acid could yield substituted 1-acetyl-2-aminomethylcyclopropanes through the acid hydrolysis of enamines to the corresponding aminoketone. To verify that possibility, various allylamine derivatives were subjected to the reaction with 2 and the reaction products were treated with acid (Scheme 2).When the reaction of anions of tosylallylamines with phenyl(propynyl)iodonium triflate was treated with aqueous acid after the completion of the addition reaction, 13 1-acetyl-2-aminomethylcyclopropanes (7) 14 were produced without any other decomposition products. As expected, Scheme 1 I + Ph -OTf n-BuLi N Ts Ph Ph HN Ts Et...

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Chemistry of bicyclo[3.1.0]hex-1-enes contrasted with that of 2-alkylidenecyclopentane-1,3-diyls

Cited by 30 publications

References 1 publication

Strain-Induced Transformations of Bicyclo[3.1.0]hex-1-enes

Strain-Induced Transformations of Bicyclo[3.1.0]hex-1-enes

Allenyl Azide Cycloaddition Chemistry: Exploration of the Scope and Mechanism of Cyclopentennelated Dihydropyrrole Synthesis through Azatrimethylenemethane Intermediates

A Stereoselective Synthesis of 1-Acetyl-2-aminomethylcyclopropanes from Allylsulfonamides and Phenyl(alkynyl)iodonium Salts

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