Rigid Alicyclic Molecules from Bicyclo[2.2.1]hept‐2‐enes (=8,9,10‐Trinorbornenes) and 1,4‐Dipyridin‐2‐ylphthalazines as Stereoselective Coupling Agents

Margetić, Davor; Murata, Yasujiro; Komatsu, Kôichi; Marinić, Željko

doi:10.1002/hlca.200800205

Cited by 12 publications

(6 citation statements)

References 28 publications

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“…This prediction is in good accordance with published results on norbornene -facial selectivity [5,[51][52][53][54]. It is evident from calculations that the cycloaddition reaction on the exo--face of the approaching 42 is greatly favored over the endo--face attack.…”

Section: Tandem Cycloadditions Of 134-oxadiazolessupporting

confidence: 91%

“…This finding is in sharp contrast with the report on the OD addition to the parent exo,endo-isomer 91 [36]. In this particular case, reaction is not stereospecific and yields the mixture of syn-and anti-facial O 5 - [5]polynorbornane exo,endo-and exo,exo-adducts 92 and 93 in approximately 2:1 ratio (Scheme 15b).…”

Section: Reactions With 7-oxanorbornenescontrasting

confidence: 85%

“…Furthermore, polycyclic bis-oxygen bridged polarofacial substrate 89 when allowed to react with OD produced exclusively angular geometry of O 5 - [5]polynorbornane 90 (Scheme 15a) [35]. This finding is in sharp contrast with the report on the OD addition to the parent exo,endo-isomer 91 [36].…”

Section: Reactions With 7-oxanorbornenesmentioning

confidence: 59%

“…Shortly after, Seitz [17], and independently at the same time Sauer [18,19], reported same reactions. In one case, the on-coupled COCOC- [5]polynorbornane 24 alongside COC- [3]polynorbornane 23 was also produced [20], presumably by reaction of 23 with 1,3-dipole 22 which must have a finite lifetime for this to occur [21]. In the course of reaction, 7oxabicyclo[2.2.1]heptane moiety is obtained at the ring junction.…”

Section: (34%) 10hmentioning

confidence: 99%

“…In a single reaction pot, two cycloaddition steps take place consecutively, new bonds are made in a process, in a continous sequence of reactions, without isolation of intermediates. Tandem [4+2]/[4+2] reactions used in the synthesis of [n]polynorbornanes include small heterocycles such as 1,2,4,5-tetrazine, [3,4] 1,2,4-triazine [3], and phthalazine [5], while tandem [4+2]/[3+2] cycloadditions use 1,3,4-oxadiazoles [6,7]. Important groups of tandem cycloaddition reactions are [4+2]/[4+2] and [4+2]/[3+2] reactions.…”

Section: Introductionmentioning

confidence: 99%

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Tandem [4+2]/[3+2] Cycloadditions of 1,3,4-Oxadiazoles with Alkenes

Margetić¹,

Trošelj²,

Johnston

2011

MROC

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A review on the tandem [4+2]/[3+2] cycloaddition reactions of 1,3,4-oxadiazoles with alkenes is presented. This reaction presents a powerful synthetic tool in the construction of complex polycyclic molecules in a one-pot reaction. Special attention is paid to synthesis of [n]polynorbornane and oxanorbornyl systems. In continuation, a review on the 1,3,4-oxadiazole reactions used in stereoselective total synthesis of alkaloids is given. Both intermolecular and intramolecular tandem [4+2]/[3+2] reactions are discussed. Stereospecificities and mechanistic rationale of various reactions are supported by quantum-chemical calculations (RHF/6-31G*). TANDEM [4+2]/[3+2] CYCLOADDITION REACTIONS OF OXADIAZOLES WITH ACYCLIC ALKENESVasil'ev reported that a series of polyfluorinated 1,3,4oxadiazoles 1-4 undergo a tandem [4+2]/[3+2] cycloadditions with acyclic alkenes, representative examples are given in Scheme 3.[15] Ethylene reacts in a sealed vessel at 200-220 o C with OD producing 1,4-bis(trifluoromethyl)-7-oxabicyclo[2.2.1]heptane 5 in 41% yield. Stereochemical or regiochemical factors come into play when the alkene bears substituents. Both regio-isomers (2,5-, 2,6-) and stereo-isomers (exo-, endo-) are then possible. The regiochemical outcome depends on the size of the substituent rather than its electronic properties. Thus, the reaction of propylene, ethyl vinyl ether, ethyl acrylate, methyl metacrylate, and isoprene give mixtures of the 2,5-and the 2,6-isomers 9-13 in each case, whereas reaction with styrene regiospecifically gave product 14. TANDEM [4+2]/[3+2] CYCLOADDITION REACTIONS OF OXADIAZOLES WITH CYCLIC ALKENESA range of cycloalkenes have been found to react with OD to form highly symmetrical coupled products 15 (n=1,2,3,5), in which the rings were exo-fused to the 7-oxanorbornane subframe (Scheme 4) [18].Reaction with cyclopentadiene proceeds in relatively mild conditions, while cyclopentene, cyclohexene and 1,4-cyclohexadiene require more drastic conditions, heating at 140-200 o C (Scheme 5) N N

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Section: Tandem Cycloadditions Of 134-oxadiazolessupporting

confidence: 91%

Section: Reactions With 7-oxanorbornenescontrasting

confidence: 85%

Section: Reactions With 7-oxanorbornenesmentioning

confidence: 59%

Section: (34%) 10hmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Tandem [4+2]/[3+2] Cycloadditions of 1,3,4-Oxadiazoles with Alkenes

Margetić¹,

Trošelj²,

Johnston

2011

MROC

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Palladium‐Catalyzed Acylation Reactions: A One‐Pot Diversified Synthesis of Phthalazines, Phthalazinones and Benzoxazinones

Suchand

Satyanarayana

2018

Eur J Org Chem

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A sequential one‐pot strategy for the diversified synthesis of phthalazines, phthalazinones and benzoxazinones was presented. This strategy proceeds through [Pd]‐catalyzed acylation and nucleophilic cyclocondensation with dinucleophilic reagents. This process was based on direct coupling with simple bench‐top aldehydes without the assistance of directing group and without activating the carbonyl group. The process is highly advantageous because it employs simple nitrogen‐based nucleophiles, and non‐toxic and readily accessible aldehydes as the carbonyl source. Most importantly, the strategy was applied to the one‐pot synthesis of PDE‐4 inhibitor.

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Dipolar Cycloaddition Reactions of Azomethine Ylides Generated by endocyclic‐exocyclic 1,3‐dipole Rearrangement

Margetić

Warrener

Butler

et al. 2014

Journal of Heterocyclic Chem

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in Wiley Online Library (wileyonlinelibrary.com).Dipolar cycloaddition of polycyclic azomethine ylides, in which the central nitrogen atom is part of a pyrrolidine ring and bears a methoxycarbonyl group with norbornenes has been shown to produce two main types of products featuring pyrrolizidine rings. In conjuction with results of quantum chemical calculations (B3LYP), mechanistic rationale was postulated. The key reaction step is unprecedented endocyclic to exocyclic azomethine ylide rearrangement by an intermolecular prototropic migration (formal [1,3] H-shift).

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Rigid Alicyclic Molecules from Bicyclo[2.2.1]hept‐2‐enes (=8,9,10‐Trinorbornenes) and 1,4‐Dipyridin‐2‐ylphthalazines as Stereoselective Coupling Agents

Cited by 12 publications

References 28 publications

Tandem [4+2]/[3+2] Cycloadditions of 1,3,4-Oxadiazoles with Alkenes

Tandem [4+2]/[3+2] Cycloadditions of 1,3,4-Oxadiazoles with Alkenes

Palladium‐Catalyzed Acylation Reactions: A One‐Pot Diversified Synthesis of Phthalazines, Phthalazinones and Benzoxazinones

Dipolar Cycloaddition Reactions of Azomethine Ylides Generated by endocyclic‐exocyclic 1,3‐dipole Rearrangement

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