Reaction of 2,5-bis-trifluoromethyl-1,3,4-oxadiazole with 7-oxanorbornenes revisited: Experimental and quantum-chemical study of reaction stereoselectivity

Margetić, Davor; Eckert‐Maksić, Mirjana; Trošelj, Pavle; Marinić, Željko

doi:10.1016/j.jfluchem.2009.12.012

Cited by 16 publications

(4 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These cycloadducts have been used to construct polycyclic aromatic hydrocarbons (Eda et al, 2015;Criado et al, 2013). The annulated 7-oxabicyclo[2.2.1]heptane moiety also acts as a framework for synthesis of molecular tweezers (Murphy et al, 2016;Warrener et al, 1999), high-molecular-weight materials (Margetic ´et al, 2010;Vogel et al, 1999) and various supramolecular systems (Abdelhamid et al, 2011;Akbari Afkhami et al, 2017;Khalilov et al, 2021;Safarova et al, 2019). Under acid catalysis, cycloaddition intermediates can be converted into phenols, cyclohexenoles, or substituted aromatic hydrocarbons (Zaytsev et al, 2019;Zubkov et al, 2012a,b).…”

Section: Chemical Contextmentioning

confidence: 99%

Crystal structure and Hirshfeld surface analysis of dimethyl 4-hydroxy-5,4′-dimethyl-2′-(toluene-4-sulfonylamino)biphenyl-2,3-dicarboxylate

Guliyeva,

Burkin,

Annadurdyyeva

et al. 2024

Acta Cryst E

View full text Add to dashboard Cite

In the title compound, C25H25NO7S, the molecular conformation is stabilized by intramolecular O—H...O and N—H...O hydrogen bonds, which form S(6) and S(8) ring motifs, respectively. The molecules are bent at the S atom with a C—SO2—NH—C torsion angle of −70.86 (11)°. In the crystal, molecules are linked by C—H...O and N—H...O hydrogen bonds, forming molecular layers parallel to the (100) plane. C—H...π interactions are observed between these layers.

show abstract

Section: Chemical Contextmentioning

confidence: 99%

Crystal structure and Hirshfeld surface analysis of dimethyl 4-hydroxy-5,4′-dimethyl-2′-(toluene-4-sulfonylamino)biphenyl-2,3-dicarboxylate

Guliyeva,

Burkin,

Annadurdyyeva

et al. 2024

Acta Cryst E

View full text Add to dashboard Cite

show abstract

“…This result compares with reaction of 2,5-di(methoxycarbonyl)-1,3,4-oxadiazole 28 with alkene 26 under thermal conditions which produced a mixture of coupled products: the major product 27b is formed by stereospecific coupling at the norbornene -bond together with the products tentatively assigned as 29 and involved cyclobutene -bond participation [6]. Analogously, 2,3-dicarbomethoxy norbornadiene 30 produced COC- [3]polynorbornane 31 in 33% yield (Scheme 7b) when reacted with OD [37]. Site selectivity was also observed in the coupling of 2,3-dimethylenenorbornene 32, which occurred exclusively at the exo-face of the norbornene -bond to give 33 (67% yield, (Scheme 7c) [23].…”

Section: Site-selectivitymentioning

confidence: 99%

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

Margetić¹,

Trošelj²,

Johnston

2011

MROC

View full text Add to dashboard Cite

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

show abstract

“…Originally inspired by the potential development of sequential intramolecular inverse electron demand Diels–Alder reactions of unsymmetrically substituted 1,2,4,5-tetrazines, − our approach ultimately enlisted an alternative cascade cycloaddition reaction of electron-deficient five-membered heterocyclic azadienes using 1,3,4-oxadiazoles in the initiating inverse electron demand Diels–Alder reaction. , Although a limited number of reports had described the cycloadditions of electron-deficient 1,3,4-oxadiazoles, they typically employed symmetrical oxadiazoles bearing two strong electron-withdrawing substituents (CF 3 , SO 2 Et, CO 2 Me) and all had been examined only in intermolecular reactions (Figure ). − Reactions of olefinic dienophiles were found to proceed through an initial [4 + 2] cycloadduct that loses N 2 to provide a carbonyl ylide that subsequently reacted again with the same olefin in a 1,3-dipolar cycloaddition reaction to provide only 2:1 cycloadducts, limiting their synthetic utility.…”

Section: Introductionmentioning

confidence: 99%

Tandem Intramolecular Diels–Alder/1,3-Dipolar Cycloaddition Cascade of 1,3,4-Oxadiazoles: Initial Scope and Applications

Sears

Boger

2016

Acc. Chem. Res.

View full text Add to dashboard Cite

Conspectus A summary of the development and initial studies on the scope of a powerful tandem intramolecular [4 + 2]/[3 + 2] cycloaddition cascade of 1,3,4-oxadiazoles is detailed and provides the foundation for its subsequent use in organic synthesis. Implemented with substrates in which both the initiating dienophile and subsequent dipolarophile are tethered to the 1,3,4-oxadiazoles, the studies expanded the scope of oxadiazoles that participate in the reaction cascade, permitted the use of differentiated dienophiles and dipolarophiles, extended their use to unsymmetrical dienophiles and dipolarophiles, provided exclusive control of the cycloaddition regioselectivities, and imposed exquisite control on the cycloaddition stereochemistry. As key reactivity and stereochemical features of the reactions were being defined, the cascade cycloaddition reaction was implemented in the total synthesis of a series of alkaloids including (−)-vindoline, (−)-vindorosine, the closely related natural products (+)-4-desacetoxyvindoline and (+)-4-desacetoxyvindorosine, natural minovine, (+)-N-methylaspidospermidine, (+)-spegazzinine, (−)-aspidospermine, and a number of key analogues. Most recently it was used in the divergent total syntheses of (+)-fendleridine, (−)-kopsinine, (−)-kopsifoline D, and (−)-deoxoapodine, in which four different strategic bonds in four different classes of the hexacyclic alkaloids were formed from a common cascade cycloaddition intermediate. A large number of vindoline analogues were prepared by variations on the cascade cycloaddition reaction for single step incorporation into analogues of vinblastine. These structural changes to vindoline permitted both systematic alterations to the peripheral substituents as well as deep-seated changes to the core structure and embedded functionality of vinblastine not previously accessible. Although explored initially for accessing vindoline and vinblastine, the use of the cycloaddition cascade in the total synthesis of an impressive range of additional natural products illustrate the power of the methodology. Alternative tethering strategies for the cascade cycloaddition reaction, combined intramolecular and intermolecular variants of either the initiating Diels–Alder reaction or the subsequent carbonyl ylide 1,3-dipolar cycloaddition, an expanded examination of the tethered dipolarophile scope, and applications to additional natural product classes represent attractive areas for future work.

show abstract

Reaction of 2,5-bis-trifluoromethyl-1,3,4-oxadiazole with 7-oxanorbornenes revisited: Experimental and quantum-chemical study of reaction stereoselectivity

Cited by 16 publications

References 39 publications

Crystal structure and Hirshfeld surface analysis of dimethyl 4-hydroxy-5,4′-dimethyl-2′-(toluene-4-sulfonylamino)biphenyl-2,3-dicarboxylate

Crystal structure and Hirshfeld surface analysis of dimethyl 4-hydroxy-5,4′-dimethyl-2′-(toluene-4-sulfonylamino)biphenyl-2,3-dicarboxylate

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

Tandem Intramolecular Diels–Alder/1,3-Dipolar Cycloaddition Cascade of 1,3,4-Oxadiazoles: Initial Scope and Applications

Contact Info

Product

Resources

About