Addition of butyllithiums to benzonorbornadiene and 1,4-dihydronaphthalene 1,4-endo-oxide

Caple, R.; Chen, Grace M. S.; Nelson, J. D.

doi:10.1021/jo00818a032

Cited by 49 publications

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“…1,4‐Epoxy‐1,4‐dihydronaphthalenes ( 1 ) are easily prepared by the Diels–Alder reaction between various benzynes and furans, and are utilized as valuable synthetic precursors to construct highly functionalized naphthalene backbones 1–9. Whereas the ring‐opening substitution reactions of 1 have been extensively developed using alkyllithium3 or transition metal reagents4 (Fe,5 Cu,6 Pd,7 Rh,8 Ni9) to afford 2‐substituted 1,2‐dihydronaphthalen‐1‐ols, there is no report related to the acid‐catalyzed nucleophilic reaction of 1 . The 1,4‐epoxy moiety of 1 can be cleaved under Brønsted acid or Lewis acid (LA) conditions to form unstable cation intermediates ( A ) and only the corresponding 1‐naphthols ( 2 ) are generated by the fast hydride shift1d (R 2 =H) and subsequent aromatization even in the presence of nucleophiles (Scheme ) 1,2…”

Section: Introductionmentioning

confidence: 99%

Lewis Acid‐Catalyzed Ring‐Opening Functionalizations of 1,4‐Epoxy‐1,4‐dihydronaphthalenes

et al. 2013

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Since 1,4-epoxy-1,4-dihydronaphthalenes are smoothly converted to 1-naphthol derivatives via unstable cation intermediates formed by the acid-catalyzed ring-opening reaction of the 1,4-epoxy moiety of 1,4-epoxy-1,4-dihydronaphthalenes, their nucleophilic functionalization using the cation intermediates as an active species is extremely difficult. We have accomplished the Lewis acid-catalyzed carboncarbon and carbon-nitrogen bond formations associated with the ring-opening of 1,4-epoxy-1,4-dihydronaphthalenes using nucleophiles such as allyltrimethylsilanes, trimethylsilyl cyanide and trimetylsilyl azide, by using the stabilization effect of the cation intermediate based on the introduction of appropriate substituents into the bridgehead positions of 1,4epoxy-1,4-dihydronaphthalenes to give the corresponding unique and multifunctionalized naphthalene derivatives. The present reactions could provide excellent regioselective functionalization methods using unsymmetrical substrates, which are quite difficult to achieve using transition metal-induced procedures. 521 Lewis Acid-Catalyzed Ring-Opening Functionalizations of 1,4-Epoxy-1,4-dihydronaphthalenes Scheme 5. Ring-opening functionalizations using nitrogenbridged substrate (11).Scheme 4. Proposed reaction mechanism.

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Section: Introductionmentioning

confidence: 99%

Lewis Acid‐Catalyzed Ring‐Opening Functionalizations of 1,4‐Epoxy‐1,4‐dihydronaphthalenes

et al. 2013

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“…The concept of using nucleophiles to open oxabicyclic starting materials was first reported more than 20 years ago by Caple et al (17). Reaction of highly strained benzooxabicyclic derivatives with an organolithium and dehydration of the products gave a route to 2-substituted naphthalenes.…”

Section: Stereocontrol Via Oxabicyclic Templatesmentioning

confidence: 99%

1994 Merck Frosst Award Lecture New strategies for the stereoselective synthesis of natural and unnatural products via organometallic reagents and catalysts

Lautens¹,

Ren²,

Delanghe³

et al. 1995

Can. J. Chem.

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Samarium in the presence of diiodomethane selectively cyclopropanates an allenic alcohol to yield a methylenecyclopropane with modest to excellent diastereoselectivity. The effect of substituents at the carbinol carbon and the allenic carbon on the diastereoselectivity was investigated. A palladium catalyst was shown to promote the intramolecular cycloaddition of the methylenecyclopropane with an electron-deficient alkyne to yield a methylenecyclopentane. The reaction was stereospecific with retention of stereochemistry as proven by X-ray diffraction. Nickel catalysts accelerate the hydroalumination of oxabicyclo[3.2. llalkenes, leading to bicyclic trialkylalanes. Upon treatment with a Lewis acid (diisobutylaluminum chloride), the trialkylalanes fragment to provide cycloheptenols. This reaction, followed by an enantioselective enzyme-catalyzed esterification, was used as a key step in a synthesis of the mevinic acid lactone.Key words: methylenecyclopropane, palladium, stereocontrol, oxabicyclic, nickel.Resume : Le samarium, en presence de diiodomtthane, transforme ~Clectivement un alcool allCnique en mtthylknecyclopropane avec une diasttrCosClectivitt allant de modeste ?I excellent. On a CtudiC l'effet d'un substituant port6 par le carbone carbinolique, et par le carbone alltnique, sur la diastCrCosClectivitC. On montre qu'une catalyse par le palladium favorise la cycloaddition intramoltculaire du mCthylknecylopropane, avec un alkyne deficient en tlectron, pour donner un mCthylknecyclopentane. La reaction est stCrCospCcifique avec rktention de la stCrCochimie tel que I'indique la diffraction de rayons X. La catalyse par le nickel acctlkre I'hydroalumination des oxabicyclo[3.2.l]alcknes conduisant aux trialkylalanes bicycliques. Ces trialkylalanes trait& par un acide de Lewis (chlorure de diisobutylaluminium) se fragmentent pour donner des cyclohepttnols. On utilise cette reaction suivie d'une esterification catalysCe par une enzyme CnantiosClective comme Ctape clC dans une synthkse de la lactone de I'acide mCvinique.Mots clbs : mCthylknecyclopropane, palladium, stCrkocontr6le, oxabicyclique, nickel.[Traduit par la rCdaction] New reactions and strategies are important for the stereoselective synthesis of natural and unnatural products having interesting architectures and (or) biological activity. Results are '

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“…The goal of these ring h4-opening reactions is to construct new carbon-heteroatom or carbon-carbon bonds within the dihydronaphthalene framework. To this end, alcohols [ 29 ], amines [ 30 ], phenols [ 31 ], and thiols [ 32 ] have been used as nucleophiles to construct new carbon-heteroatom bonds and Grignard [ 33 ], organoaluminum [ 34 ], organoboron [ 35 ], organocuprate [ 36 ], organolithium [ 37 ], and organozinc reagents [ 38 ] have been used as the source of carbon nucleophiles to construct new carbon-carbon bonds.…”

Section: Introductionmentioning

confidence: 99%

Recent Advances in Transition Metal-Catalyzed Reactions of Oxabenzonorbornadiene

Boutin

Koh

Tam

2019

COS

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Background: Oxabenzonorbornadiene (OBD) is a useful synthetic intermediate capable of undergoing multiple types of transformations due to three key structural features: a free alkene, a bridged oxygen atom, and a highly strained ring system. Most notably, ring-opening reactions of OBD using transition metal catalysts and nucleophiles produce multiple stereocenters in a single step. The resulting dihydronaphthalene framework is found in many natural products, which have been shown to be biologically active. Objective: This review will provide an overview of transition metal-catalyzed reactions from the past couple of years including cobalt, copper, iridium, nickel, palladium and rhodium- catalyzed reactions. In addition, the recent derivatization of OBD to cyclopropanated oxabenzonorbornadiene and its reactivity will be discussed. Conclusion: It can be seen from the review, that the work done on this topic has employed the use of many different transition metal catalysts, with many different nucleophiles, to perform various transformations on the OBD molecule. Additionally, depending on the catalyst and ligand used, the stereo and regioselectivity of the product can be controlled, with proposed mechanisms to support the understanding of such reactions. The use of palladium has also generated a cyclopropanated OBD, with reactivity similar to that of OBD. An additional reactive site exists at the distal cyclopropane carbon, giving rise to three types of ring-opened products.

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Addition of butyllithiums to benzonorbornadiene and 1,4-dihydronaphthalene 1,4-endo-oxide

Cited by 49 publications

References 0 publications

Lewis Acid‐Catalyzed Ring‐Opening Functionalizations of 1,4‐Epoxy‐1,4‐dihydronaphthalenes

Lewis Acid‐Catalyzed Ring‐Opening Functionalizations of 1,4‐Epoxy‐1,4‐dihydronaphthalenes

1994 Merck Frosst Award Lecture New strategies for the stereoselective synthesis of natural and unnatural products via organometallic reagents and catalysts

Recent Advances in Transition Metal-Catalyzed Reactions of Oxabenzonorbornadiene

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