Facile Synthesis of Bicyclic Amidines and Imidazolines from 1,2-Diamines

Zhu, Qiang; Lü, Yixin

doi:10.1021/ol101747n

Cited by 26 publications

(19 citation statements)

References 37 publications

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“…Known methods for mono‐protection of compound 8 by the Cbz group are either multi‐staged24 or require use of a large access of the precious chiral amine 8 , in both cases yields of the target molecule were poor 25. Mono‐Cbz‐protected 1,2‐diaminodiphenylethane 12 was applied26 as starting compound without a description of its synthesis. We synthesized compounds 11 and 12 by treatment of the corresponding trans ‐diamines 8 and 9 with O ‐benzyl‐ O′ ‐phenyl carbonate 10 , which had been earlier applied for the acylation of achiral amines 27.…”

Section: Resultsmentioning

confidence: 99%

Chiral Primary Amine Tagged to Ionic Group as Reusable Organocatalyst for Asymmetric Michael Reactions of C‐Nucleophiles with α,β‐Unsaturated Ketones

et al. 2012

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The first primary amine-derived organocatalyst modified with an ionic group for asymmetric Michael reactions of C-nucleophiles with a,b-unsaturated ketones was synthesized. In the presence of this catalyst and an acidic co-catalyst (AcOH), hydroxycoumarin and its sulfur-containing analogue reacted with benzylideneacetone derivatives or cyclohexenone to afford the corresponding Michael adducts in high yields (up to 97%) and with reasonable enantioselectivity (up to 80%). The catalyst could be easily recovered and efficiently reused three times, afterwards, its activity and stereodifferentiating ability gradually declined. The analysis of recovered catalyst samples by ESI-MS allowed us to detect undesirable side reactions that poisoned the catalyst, and propose an approach for its reactivation.

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Section: Resultsmentioning

confidence: 99%

Chiral Primary Amine Tagged to Ionic Group as Reusable Organocatalyst for Asymmetric Michael Reactions of C‐Nucleophiles with α,β‐Unsaturated Ketones

et al. 2012

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“…Zhu and Lu developed a new method to synthesize chiral imidazolines from carboxy amides (28) and 1,2diamines (30) (Scheme 7). [31] The reaction was initiated by the formation of in situ imidoyl chloride (29) from carboxy amide by using phosphorous pentachloride (PCl 5 ). This intermediate 29 further reacts with Nprotected diamine 30 to form intermediate amidine (31).…”

Section: Methods A: Synthesis Of Imidazolines From 12-diaminesmentioning

confidence: 99%

“…[31] The reaction was initiated by the formation of in situ imidoyl chloride (29) from carboxy amide by using phosphorous pentachloride (PCl 5 ). This intermediate 29 further reacts with Nprotected diamine 30 to form intermediate amidine (31). Removal of the protecting group set the critical stage of cyclization to afford imidazoline (32).…”

Section: Methods A: Synthesis Of Imidazolines From 12-diaminesmentioning

confidence: 99%

Recent Advances in the Synthesis of Imidazolines (2009–2020)

Mehedi

Tepe

2020

Adv Synth Catal

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Imidazoline is an important class of compounds found in numerous natural and pharmaceutical products. The compounds are also used as an intermediate in the synthesis of organic molecules. Moreover, chiral imidazolines are widely utilized as organocatalysts to synthesize various natural and synthetic organic compounds. In the past decade, there was an increase in interest in developing new methods to synthesize these imidazoline analogs. Both modification of the previously established methods and the development of new methods are carried out significantly. This review article highlights the progress of the synthesis of imidazoline scaffolds in the last few years (2009-present). The review also described the proposed mechanism illustrated in many of the reports.

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“…Compound 3 was converted to the N-acyl derivative 5 by the reaction with 2-chlorobenzoyl chloride in basic medium. In the 1 H NMR spectrum of compounds 3 and 4, while the imidazoline ring protons signals appeared at 3.0-4.0 ppm, the imidazoline methylene carbon signals were not observed in the APT 13 C NMR spectrum. However, when the APT 13 C NMR spectrum was taken over a very long time using CDCl3, these signals were observed very weakly.…”

Section: Resultsmentioning

confidence: 85%

“…10,11 Besides, effective and new enantioselective methods have been improved for the synthesis of chiral imidazoline compounds over the last years. 12,13 Imidazoline compounds are widely studied by organic chemists with regard to their different application areas as synthetic intermediates, protecting groups, chiral auxiliaries and catalysts for asymmetric synthesis. In recent years, they have gained importance as organocatalysts [14][15][16] in very diverse stereoselective reactions due to their basicity and nucleophilicity 17 as well as Brønsted acidity 18,19 of their salts.…”

Section: Introductionmentioning

confidence: 99%