Molecular design by cycloaddition reactions. 34. Cycloaddition reactions of 1,4-[(tert-butyloxycarbonyl)imino]-1,4-dihydronaphthalene

Sasaki, Tadashi; Manabe, Takashi; Nishida, S.

doi:10.1021/jo01291a019

Cited by 19 publications

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“…15 The resultant mixture of C 2 -isomer 20a and σ-isomer 20b is not separated but deazetised photochemically to the common bis-aziridine 21. 10 Reaction of 21 with N-Boc-7-azabenzonorbornadiene 15 produced the [5]polynorbornane 22 10 containing four aza-bridges. The structure of 22 was again determined by NMR spectral symmetry at elevated temperature.…”

Section: Methodsmentioning

confidence: 99%

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A 1,3-Dipolar Cycloaddition Route to 7-Azanorbornanes: Application to the Synthesis of syn-Facial N-Bridged Polynorbornanes

Butler¹,

Malpass²,

Margetić³

et al. 1998

Synlett

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Aziridinocyclobutenes react with electron-deficient or ringstrained alkenes to produce 7-azanorbornenes in a novel 1,3-dipolar cycloaddition reaction suitable for BLOCK assembly protocols. Benzo-7-azanorbornadiene and 7-heterobridged analogues react stereoselectively to produce compounds with syn-facial orientation of their bridges. 7-Azanorbornanes have received much interest following the discovery of the analgesic properties of epibatidine 1 (Scheme 1) and several specialist syntheses of this alkaloid have appeared in the recent literature. 4 Higher norbornalogues of 7-azanorbornanes, on the other hand, are uncommon and one of the rare examples is the doubly Nbridged adduct 2 reported by Sasaki et al. as the minor product (21%) in the cycloaddition of N-t Boc-isoindole with N-t Boc-7-azabenzonorbornadiene. 5 Scheme 1Following the success of our recently described ACE reaction (Scheme 2, equation 1) for the synthesis of 7-oxanorbornenes, 6 we reasoned that the development of an aziridine equivalent (aza-ACE reaction, Scheme 2, equation 2) held much potential for the synthesis of N-bridged alicyclics, especially 7-azanorbornanes. This is the subject of the present letter where we demonstrate the versatility of this new BLOCK reaction by the synthesis of the first examples of syn-facial polynorbornane systems containing multiple N-bridges. 7 Scheme 2The aziridinocyclobutane 8 required to test the potential of the aza-ACE coupling reaction was prepared as outlined in Scheme 3. Conversion of the benzonorbornadiene 3 8 to the cyclobutene-1,2-diester 4 followed the established method of Mitsudo and co-workers, which employs the ruthenium-catalysed addition of dimethyl acetylene dicarboxylate 4 (DMAD). 9 Conversion of cyclobutene 5 to the triazoline 7 10 was achieved by thermal addition of benzyl azide 6 and elimination of dinitrogen to produce aziridine 8 10 was conducted photochemically (Hanovia 450 watt Hg lamp, quartz, benzene, RT). The synthesis of aziridinocyclobutane 8 was achieved in 40% overall yield for the three step process from the readily available benzonorbornadiene 3.The reactivity of the N-benzyl aziridinocyclobutane 8 towards 1,3-dipolar cycloaddition was assessed initially by reaction with excess DMAD 4 (benzene at reflux) which produced the 1:1-adduct 10. 10 The structure of 10 was supported by NMR data and presumed to arise via attack of the DMAD onto the α-face of the 1,3-dipolar intermediate 9, formed by ring-opening of the aziridine (Scheme 3). Support for this proposal is provided by the formation of a yellow colour when aziridine 8 is heated alone in toluene. 11 Colour formation is lost on cooling and regenerated on heating, indicating the reversibility of the ring-opening process; further, the colour is discharged immediately on the addition of dipolarophiles like dimethyl fumarate. Scheme 3High stereoselectivity is observed in the reaction of the aziridine 7 with ethylenic dienophiles, eg maleic anhydride 11 forms a single product, shown to be the exo-fused adduct 12 10 by the existence of ...

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Section: Methodsmentioning

confidence: 99%

“…4 Higher norbornalogues of 7-azanorbornanes, on the other hand, are uncommon and one of the rare examples is the doubly Nbridged adduct 2 reported by Sasaki et al as the minor product (21%) in the cycloaddition of N-t Boc-isoindole with N-t Boc-7-azabenzonorbornadiene. 5…”

mentioning

confidence: 99%

A 1,3-Dipolar Cycloaddition Route to 7-Azanorbornanes: Application to the Synthesis of syn-Facial N-Bridged Polynorbornanes

Butler¹,

Malpass²,

Margetić³

et al. 1998

Synlett

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“…The work of Sasaki, [26] modelled after the earlier study reported by Fieser and Haddadin in the O,O-series, [27] was the flagship in the area of N-hetero-bridged benzo-fused sesquinorbornanes. Entry to N,O-bridged and ,N-bridged [2]polynorbornanes was achieved by reaction of N-Boc-isoindole 81a with the π bond of 7-oxa-benzonorbornadiene (80a) or N-Boc-7-azabenzonorbornadiene (80b) (Scheme 11).…”

Section: Hetero-bridged Benzosesquinorbornadienesmentioning

confidence: 99%

ChemInform Abstract: New Adventures in the Synthesis of Hetero‐Bridged syn‐Facially Fused Norbornadienes (“[n]Polynorbornadienes”) and Their Topological Diversity

Warrener¹

2001

ChemInform

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Section: Hetero-bridged Benzosesquinorbornadienesmentioning

confidence: 99%

New Adventures in the Synthesis of Hetero-Bridgedsyn-Facially Fused Norbornadienes (“[n]Polynorbornadienes”) and Their Topological Diversity

Warrener

2000

Eur. J. Org. Chem.

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Molecular Scaffolds formed by the linking of bicyclo[2.2.1]heptane (norbornane) subunits by sharing a common C 2bridge have great appeal to the molecular architect since modelling studies have shown that the syn-facially fused members have a curved topology. Furthermore, this curvature can be modified by replacement of the methylene bridge by heteroatom bridges (O, S, NR), and made rod-like by introducing a σ-bond between adjoining methylene bridges in sesquinorbornane subunits. This review presents synthetic methodology which allows the stereocontrolled construction [a] ). His research interests have focused on synthetic methodology involving cycloaddition chemistry (isobenzo systems) and photochemistry (small ring synthesis), with occasional forays into natural product synthesis (daunomycin, nucleosides, protoberberine). At the ANU, he set up a Centre for Forensic Science specialising in fingerprint detection, and has been the driving force behind the creation of the Centre for Molecular Architecture at CQU. He has published more than 250 research papers and was awarded a senior ARC Research Fellowship (1992Ϫ1996) and the RACI Organic Medal in 1996.MICROREVIEWS: This feature introduces the readers to the authors' research through a concise overview of the selected topic. Reference to important work from others in the field is included.

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Molecular design by cycloaddition reactions. 34. Cycloaddition reactions of 1,4-[(tert-butyloxycarbonyl)imino]-1,4-dihydronaphthalene

Cited by 19 publications

References 0 publications

A 1,3-Dipolar Cycloaddition Route to 7-Azanorbornanes: Application to the Synthesis of syn-Facial N-Bridged Polynorbornanes

A 1,3-Dipolar Cycloaddition Route to 7-Azanorbornanes: Application to the Synthesis of syn-Facial N-Bridged Polynorbornanes

ChemInform Abstract: New Adventures in the Synthesis of Hetero‐Bridged syn‐Facially Fused Norbornadienes (“[n]Polynorbornadienes”) and Their Topological Diversity

New Adventures in the Synthesis of Hetero-Bridgedsyn-Facially Fused Norbornadienes (“[n]Polynorbornadienes”) and Their Topological Diversity

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