Iridium-catalyzed asymmetric ring-opening of azabicyclic alkenes with alcohols

Yang, Dingqiao; Xia, Jiuyun; Long, Yuhua; Zeng, Zhongyi; Zuo, Xiongjun; Wang, Sanyong; Li, Chunrong

doi:10.1039/c3ob40891d

Cited by 38 publications

(19 citation statements)

References 83 publications

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“…Therefore, among the ligands screened, achiral ligand DPPF was the most effective one in terms of yield, which afforded 3aa in 94% yield within 4 hours (entry 3). The impact of the amount of catalyst loading on the reaction was then investigated (entries [13][14][15][16], and it was observed that the yield of 3aa was strongly influenced by the amount of catalyst loading. The yield of 3aa increased as the amount of catalyst loading gradually increased to 1.5 mol% (entries 3, 13, 14), and the best yield could be obtained in the presence of 1.5 mol% of [Ir(COD)Cl] 2 with 3.0 mol% DPPF (entry 3).…”

Section: Paper Syn Thesismentioning

confidence: 99%

Iridium-Catalyzed Anti-Stereoselective Ring-Opening Reactions of Azabicyclic Alkenes with Fluoroalkylamines

Yang

Guo

et al. 2017

Synthesis

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A novel iridium-catalyzed ring-opening reaction of azabicyclic alkenes with a variety of fluoroalkylamines was developed. The reaction gave a series of fluorinated trans-1,2-diamine derivatives in good to excellent yields (up to 98%) under relatively mild conditions. The effects of various ligands, catalyst loading, solvents, and temperatures on the yield of the reaction were also investigated. This is the first time that fluorinated compounds were synthesized by incorporating a series of fluoroalkylamines into hydronaphthalene skeleton.

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Section: Paper Syn Thesismentioning

confidence: 99%

Iridium-Catalyzed Anti-Stereoselective Ring-Opening Reactions of Azabicyclic Alkenes with Fluoroalkylamines

Yang

Guo

et al. 2017

Synthesis

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“…As azabenzonorbornadienes are less reactive than the corresponding oxabenzonorbornadienes,, this kind of reaction was mainly focused on the oxabenzonorbornadienes. Although amines have been successfully applied,, the development of efficient catalytic system for the asymmetric ring opening reactions of azabenzonorbornadienes with other heteronucleophiles is necessary . Our group has a continuous interest in the asymmetric ring opening reactions of oxa‐/azabenzonorbornadienes and has applied terminal alkynes, phenols, and amines as suitable nucleophiles using the strategy of combination of transition metal complexes with Lewis acids as co‐catalytic systems.…”

Section: Screening Of Chiral Ligands[a]mentioning

confidence: 99%

Enantioselective Ring Opening Reactions of Azabenzonorbornadienes with Carboxylic Acids

Zhou

Chen

et al. 2016

Adv Synth Catal

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Thep alladium/silver (Pd/Ag)c o-catalytic system was found to be effective for the enantioselective ring opening reactions of the low reactive azabenzonorbornadienes with weak nucleophilic carboxylic acids.B oth aryl and alkyl carboxylic acids are suitable nucleophiles and afforded the cis ring opening productsi ng ood yieldsw ith excellent enantioselectivities. Thea bsolute configuration of one of the products hasb eenc onfirmed by X-ray crystal structurea nalysis,a nd ap lausible reaction pathway is proposed. Keywords: asymmetric synthesis;a zabenzonorbornadienes;c arboxylic acids;c o-catalysts;r ing opening reactionSubstituted hydronaphthalenes are versatile building motifsi no rganic synthesis and widely exist in natural productsa nd bioactive molecules. [1] Thea symmetric ring opening reactions of oxa-/azabenzonorbornadienes with heteroatomn ucleophiles have provided powerful synthetic methods for the construction of substituted hydronaphthalenes with multiple chiral centers and have been extensively studied. [2] After Lautens group had pioneered the elegant works on these asymmetric ring opening reactions of oxa-/azabenzonorbornadienes, [3] fruitful results were obtained by the groups of Yang, [4] Luo, [5] ando thers. [6] As azabenzonorbornadienes are less reactive than the corresponding oxabenzonorbornadienes, [3d,5] this kind of reaction was mainly focused on the oxabenzonorbornadienes.A lthough amines have been successfully ap-plied, [3d,4a] the developmento fe fficient catalytic systemf or the asymmetric ring opening reactions of azabenzonorbornadienesw ith other heteronucleophiles is necessary. [7] Our group hasacontinuous interesti nt he asymmetricr ing opening reactions of oxa-/azabenzonorbornadienes and hasa pplied terminal alkynes, [8] phenols, [9] and amines [10] as suitable nucleophiles using the strategy of combination of transition metal complexes with Lewis acids as co-catalytic systems.I no ur continuing research on this topic we proposedt hat carboxylica cids,w hich are weaker nucleophiles comparedw ith aminesa nd phenols,c ould also be applied in the asymmetric ringo pening reactions of azabenzonorbornadienes.B ya pplying the transitionm etal/Lewis acid co-catalytics ystem, we have realized the asymmetric ring opening reactions of azabenzonorbornadienes by carboxylic acids with excellent enantioselectivities (94-99%) andr eport our results herein. To the best of our knowledge, the asymmetric ring opening reactiono fa zabenzonorbornadienebycarboxylic acid has not been demonstrated to date.We embarked on this investigation by screeningf or as uitable chiral ligandu sing Pd(OAc) 2 [11] and AgBF 4 as co-catalyst. As the results in Table 1show,aninitial survey with the monodentate phosphine ligand( R)-MOP andt he chelating phosphinel igand (R,S)-PPF-PtBu gave no desired product (Table 1, entries 1a nd 2). By using (R)-Binap,w ew ere delighted to observe an encouraging resultw ith excellent enantioselectivity (Table 1, entry 3). Some other chiral biaryl ligands were also tested, the results ind...

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“…However, bulky steric hindrance in nucleophiles seemed necessary to ensure high enantioselectivities. Catalyzed by iridium complexes, the ARO reactions of azabenzonorbornadienes with alcohols and phenols were also reported, but the results were not satisfactory due to low to moderate ee’s obtained in many cases. The development of new and efficient catalysts or catalytic systems for ARO reactions of azabenzonorbornadienes is still interesting and necessary.…”

mentioning

confidence: 90%

Palladium/Lewis Acid Co-catalyzed Divergent Asymmetric Ring-Opening Reactions of Azabenzonorbornadienes with Alcohols

Yang

Chen

et al. 2016

Org. Lett.

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By fine tuning the combinations of chiral palladium catalysts and Lewis acids, both the additional and reductive asymmetric ring-opening reactions of azabenzonorbornadienes with alcohols were accomplished with good chemoselectivity, regioselectivity, and enantioselectivity. It was proven that the reductive ring-opening products were generated through a transfer-hydrogenation process with alcohols as hydrogen source.

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Iridium-catalyzed asymmetric ring-opening of azabicyclic alkenes with alcohols

Cited by 38 publications

References 83 publications

Iridium-Catalyzed Anti-Stereoselective Ring-Opening Reactions of Azabicyclic Alkenes with Fluoroalkylamines

Iridium-Catalyzed Anti-Stereoselective Ring-Opening Reactions of Azabicyclic Alkenes with Fluoroalkylamines

Enantioselective Ring Opening Reactions of Azabenzonorbornadienes with Carboxylic Acids

Palladium/Lewis Acid Co-catalyzed Divergent Asymmetric Ring-Opening Reactions of Azabenzonorbornadienes with Alcohols

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