Stereoselective Lewis base catalyzed formal 1,3-dipolar cycloaddition of azomethine imines with mixed anhydrides

Hesping, Lena; Biswas, Anup; Daniliuc, Constantin G.; Mück‐Lichtenfeld, Christian; Studer, Armido

doi:10.1039/c4sc02612h

Cited by 64 publications

(36 citation statements)

References 66 publications

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“…52 A new type of 1,3-DC has been recently performed with azomethine imines 57 and Nacyliminium ions 105 affording cycloadducts 103 (Scheme 35). 53 The chiral Lewis base 104 acted as organocatalyst forming the corresponding activated intermediates 105 by reaction with mixed anhydrides. Another family of isoquinolinium ylides are the corresponding unsaturated systems which should be prepared in situ in a two-or three-component reactions.…”

Section: Scheme 31 [4+3] Cycloaddition Of Azomethine Imines 57 With Dmentioning

confidence: 99%

1,3-Dipolar cycloadditions of azomethine imines

2015

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Azomethine imines are considered 1,3-dipoles of the aza-allyl type which are transient intermediates and should be generated in situ but can also be stable and isolable compounds. They react with electron-rich and electron-poor olefins as well as with acetylenic compounds and allenoates mainly by a [3 + 2] cycloaddition but they can also take part in [3 + 3], [4 + 3], [3 + 2 + 2] and [5 + 3] with different dipolarophiles. These 1,3-dipolar cycloadditions (1,3-DC) can be performed not only under thermal or microwave conditions but also using metallo- and organocatalytic systems. In recent years enantiocatalyzed 1,3-dipolar cycloadditions have been extensively considered and applied to the synthesis of a great variety of dinitrogenated heterocycles with biological activity. Acyclic azomethine imines derived from mono and disubstituted hydrazones could be generated by prototropy under heating or by using Lewis or Brønsted acids to give, after [3 + 2] cycloadditions, pyrazolidines and pyrazolines. Cyclic azomethine imines, incorporating a C-N bond in a ring, such as isoquinolinium imides are the most widely used dipoles in normal and inverse-electron demand 1,3-DC allowing the synthesis of tetrahydro-, dihydro- and unsaturated pyrazolo[1,5-a]isoquinolines in racemic and enantioenriched forms with interesting biological activity. Pyridinium and quinolinium imides give the corresponding pyrazolopyridines and indazolo[3,2-a]isoquinolines, respectively. In the case of cyclic azomethine imines with an N-N bond incorporated into a ring, N-alkylidene-3-oxo-pyrazolidinium ylides are the most popular stable and isolated dipoles able to form dinitrogen-fused saturated and unsaturated pyrazolopyrazolones as racemic or enantiomerically enriched compounds present in many pharmaceuticals, agrochemicals and other useful chemicals.

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Section: Scheme 31 [4+3] Cycloaddition Of Azomethine Imines 57 With Dmentioning

confidence: 99%

1,3-Dipolar cycloadditions of azomethine imines

2015

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“…In 2015, Studer, Mück-Lichtenfeld, and co-workers reported the synthesis of complex pyrazolidinone-fused THIQs 22 by 1,3-dipolar cycloaddition of C,N-cyclic N′-benzoyl azomethine imines with activated arylacetic acid derivatives generated in situ from the corresponding acids 20 (Scheme 10). 38 Under the optimal conditions, reactions proceeded smoothly in high yields with good to excellent diastereo-and enantioselectivities. The use of N-heterocyclic carbene (NHC) catalyst under oxidative conditions was in-Scheme 9 Enantioselective addition of terminal alkynes to isolated isoquinoline iminiums 17 examples R 1 = alkyl, 3:1 to 8:1 dr, 65-93% yield, 90 to >99% ee R 1 = Ph, >20:1 dr, 30% yield, 55% ee…”

Section: Ned [3+2] Cycloaddition Of Cn-cyclic N′-acyl Azomethine Iminesmentioning

confidence: 96%

Asymmetric Synthesis of C1-Chiral THIQs with Imines in Isoquinoline Rings

Chen

Gao

2020

Synthesis

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Tetrahydroisoquinoline (THIQ) scaffolds are important structural units that widely exist in a variety of natural alkaloids and synthetic analogues. Asymmetric synthesis of C1-chiral THIQ is of particular importance due to its significant pharmaceutical, agrochemical, and other biological activities, and the usually distinct bioactivities exhibited by the two enantiomers. In this review, we highlight the significant advances achieved in this field, present recent asymmetric synthesis with imines in isoquinoline rings ordered according to the sequence of various substrate types. New strategies could be inspired and more types of substrates need further development.1 Introduction2 Catalytic Asymmetric Reaction of Dihydroisoquinolines2.1 Asymmetric Reactions of 3,4-Dihydroisoquinolines2.2 Asymmetric Reactions of Dihydroisoquinolinium Salts2.3 Asymmetric Reactions of C,N-Cyclic N′-Acyl Azomethine Imines2.3.1 NED [3+2] Cycloaddition of C,N-Cyclic N′-Acyl Azomethine Imines2.3.2 IED [3+2] Cycloaddition of C,N-Cyclic N′-Acyl Azomethine Imines2.3.3 [3+3] Cycloaddition of C,N-Cyclic N′-Acyl Azomethine Imines2.3.4 [4+3] Cycloaddition of C,N-Cyclic N′-Acyl Azomethine Imines2.3.5 Asymmetric Addition Reactions to C,N-Cyclic N′-Acyl Azomethine Imines2.4 Asymmetric Reactions of C,N-Cyclic Nitrones3 Catalytic Asymmetric Mannich Reactions of Isoquinolines4 Conclusions and Perspectives

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“…With the optimized reaction conditions in hand, we investigated the substrate scope of this cascade reaction (Scheme 4). Ther esults show that substrates bearing either a para-substituted electron-rich or electron-deficient phenyl ring (R 3 )r eacted smoothly under the optimized reaction conditions to afford the corresponding bridged heterocycles (13 b-e)i ng ood yields.A na liphatic cyclohexyl substituent was also well tolerated as R 3 to afford 13 f in moderate yield, while the introduction of a tert-butyl group at this position resulted in al ow yield of the corresponding bridged heterocycle 13 g because of steric hindrance.I nc ontrast to the intermolecular reaction of 7e (Table 1, entry 11), it is worth noting that as ubstrate bearing an ester moiety as part of R 3 reacted well under these reaction conditions,t hus affording the desired product 13 h in 56 %yield (Scheme 4). Substrates bearing amethyl substituent at either R 1 or R 2 also reacted as expected, thus providing the desired products 13 i and 13 j in moderate yields.A dditionally,o ther cycloalkenes instead of cyclohexenyl moiety were found to be amenable to our cascade reaction, with the corresponding cycloadducts 13 k and 13 l being formed.…”

Section: Angewandte Chemiementioning

confidence: 99%

“…[2] Considerable research efforts have therefore been devoted to the synthesis of various functionalized dipoles. [3] However,v ery little is known about the chemistry of azomethine ylides bearing an alkoxy group on their nitrogen atom, despite their synthetic potential. [4] Thealkoxy group in these systems can be used as at ether for intramolecular cycloaddition reactions,a nd could potentially affect the general properties and reactivity of the azomethine ylide and the cycloadduct.…”

mentioning

confidence: 99%

Gold‐Catalyzed [3+2]/Retro‐[3+2]/[3+2] Cycloaddition Cascade Reaction of N‐Alkoxyazomethine Ylides

et al. 2017

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Anovel cascade reaction has been developed for the synthesis of 2,6-methanopyrrolo [1,2-b]isoxazoles based on the gold-catalyzed generation of an N-allyloxyazomethine ylide. This reaction involves sequential [3+ +2]/retro-[3+ +2]/[3+ +2] cycloaddition reactions,t hus providing facile access to fused and bridged heterocycles which would be otherwise difficult to prepare using existing synthetic methods.Notably,this reaction allows the efficient construction of three CÀCbonds,one CÀO bond, one CÀNb ond and one CÀHb ond, as well as the cleavage of one CÀCbond, one CÀObond and one CÀHbond in as ingle operation. The intermolecular cycloaddition of an N-allyloxyazomethine ylide and the subsequent application of the product to the synthesis of tropenol is also described. Scheme 1. Cycloadditions cascade of N-alkoxyazomethine ylide.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: http://dx.

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Stereoselective Lewis base catalyzed formal 1,3-dipolar cycloaddition of azomethine imines with mixed anhydrides

Abstract: Pyrazolidinones with a tetrahydroisoquinoline core are obtained with excellent diastereocontrol and high enantioselectivity. Theoretical studies give insight on the reaction mechanism.

Cited by 64 publications

References 66 publications

1,3-Dipolar cycloadditions of azomethine imines

1,3-Dipolar cycloadditions of azomethine imines

Asymmetric Synthesis of C1-Chiral THIQs with Imines in Isoquinoline Rings

Gold‐Catalyzed [3+2]/Retro‐[3+2]/[3+2] Cycloaddition Cascade Reaction of N‐Alkoxyazomethine Ylides

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