Recent progress in a chiral multinucleating system utilizing tartaric acid esters

Ukaji, Yutaka; Inomata, Katsuhiko

doi:10.1002/tcr.201000002

Cited by 23 publications

(6 citation statements)

References 37 publications

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“…In this case only 20 mol% of DIPT, one equivalent of MgBr 2 and 1.5 equivalents of n-BuMgCl were used providing also the trans-cycloadducts 230 in 23-93% yield and 63-93% ee. 133,134 In the proposed transition state 229, the azomethine imine is coordinated to magnesium by the nitrogen and the carbonyl group to afford pyrazolidinones 230 (Scheme 88). The same group has developed a desymmetrization of 1,4-pentadien-3-ol by the asymmetric 1,3-DC of azomethine imines using magnesium diisopropyl tartrate as chiral Lewis acid in up to 98% ee.…”

Section: Other Metal-catalyzed Cycloadditionsmentioning

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: Other Metal-catalyzed Cycloadditionsmentioning

confidence: 99%

1,3-Dipolar cycloadditions of azomethine imines

2015

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“…Approach based on the activation of a moderately reactive arylnitroso dienophile; coordination of the diene: The Inomata group studied a different system utilizing the coordination of a hydroxylated diene to a tartaric acid ester [150–152]. When they examined the enantioselective hetero-Diels–Alder reaction between nitrosobenzene and ( E )-2,4-pentadien-1-ol ( 225 ) (Scheme 44), they obtained the corresponding dihydro-1,2-oxazine 226 as a mixture of regioisomers.…”

Section: Reviewmentioning

confidence: 99%

“…The ee values for the major products 226a and 226b were 33% and 55%, respectively. This modest enantioselectivity encouraged the Inomata group to further investigate the reaction [152]. …”

Section: Reviewmentioning

confidence: 99%

Stereo- and regioselectivity of the hetero-Diels–Alder reaction of nitroso derivatives with conjugated dienes

Brulíková

Harrison

Miller

et al. 2016

Beilstein J. Org. Chem.

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SummaryThe hetero-Diels–Alder reaction between a nitroso dienophile and a conjugated diene to give the 3,6-dihydro-2H-1,2-oxazine scaffold is useful for the synthesis of many biologically interesting molecules due to the diverse opportunities created by subsequent transformations of the resulting 1,2-oxazine ring. This review discusses the rationale for the observed regio- and stereoselectivity and the methods developed in recent years used to control and improve the stereo- and regioselectivity for the synthesis of 1,2-oxazine scaffolds.

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“…Inspired by the discovery of tartaric acid‐based chiral auxiliary for the asymmetric transformation of organoboron compounds, [19] Schaus group exposed another protocol employing Ho(OTf) 3 /(+)‐tartaric acid combination towards the enantioselective DA cycloaddition (Scheme 3a) [20] . Here, Ho(OTf) 3 acts as the Lewis acid, whereas (+)‐tartaric acid functions as the Brønsted acid resulting from the in situ generations of oxidopyrylium intermediate from isochromene acetals.…”

Section: Asymmetric [4+2] Cycloaddition Using Organoboron Compoundmentioning

confidence: 99%

Organoboron Compounds Towards Asymmetric Pericyclic Reaction; Exploitation to Bioactive Molecule Synthesis

et al. 2022

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Organic frameworks containing boron as one of the units have wide application in organic synthesis. Due to the non‐toxicity and cheap accessibility, the organoboron compounds have gained increased demand towards the organic chemist. Besides, there has been a huge progress in the area of chiral organoboron synthesis, which allows direct access to chiral synthons. Among other methods developed for the asymmetric synthesis of organoboron compounds, pericyclic reaction plays an important role. Cycloaddition reactions using vinyl boronic esters have been extensively reported for the synthesis of cyclic boronic esters. Asymmetric cycloaddition using organoboron compound opens a quick access to various intermediates with multiple chiral centers, which has been utilized for the total synthesis of bioactive molecules. This mini‐review outlines various asymmetric pericyclic reactions developed to date demonstrating its applicability towards bioactive molecule synthesis.

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Recent progress in a chiral multinucleating system utilizing tartaric acid esters

Cited by 23 publications

References 37 publications

1,3-Dipolar cycloadditions of azomethine imines

1,3-Dipolar cycloadditions of azomethine imines

Stereo- and regioselectivity of the hetero-Diels–Alder reaction of nitroso derivatives with conjugated dienes

Organoboron Compounds Towards Asymmetric Pericyclic Reaction; Exploitation to Bioactive Molecule Synthesis

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