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Catalysis and New Reactivities of Azadiene Cycloaddition.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Catalysis and New Reactivities of Azadiene Cycloaddition./
Author:	Zhu, Zixi.
Description:	1 online resource (394 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 85-03, Section: B.
Contained By:	Dissertations Abstracts International85-03B.
Subject:	Chemistry. -
Online resource:	click for full text (PQDT)
ISBN:	9798380375443

Catalysis and New Reactivities of Azadiene Cycloaddition.
Zhu, Zixi.

Catalysis and New Reactivities of Azadiene Cycloaddition. - 1 online resource (394 pages)

Source: Dissertations Abstracts International, Volume: 85-03, Section: B.

Thesis (Ph.D.)--The Scripps Research Institute, 2024.

Includes bibliographical references

The Diels−Alder cycloadditions of heterocyclic and acyclic azadienes are powerful reactions widely employed in organic synthesis, medicinal chemistry campaigns, and as tools in chemical biology. However, despite the fact that this reaction has been explored for more than 60 years since its discovery and now countless examples are reported, there has been no general method to catalyze or promote the azadiene cycloaddition reactions and the known approaches are restricted in substrate scope. Moreover, there was only a single mode of cycloaddition (C3/C6 cycloaddition) for the most widely recognized 1,2,4,5-tetrazine and the alternative mode (e.g. N1/N4 cycloaddition) remained unknown. Herein, studies on solvent hydrogen bonding-promoted azadiene Diels−Alder reactions as well as the unprecedented N1/N4 cycloaddition reactivity are summarized.First, the use of perfluoroalcohols (HFIP, TFE, etc.) in the promotion of azadiene cycloadditions recently discovered in the Boger group is generalized through examination of a complete range of azadienes, and other features such as impact on regioselectivity and limitations are also described. Second, in the course of examination of the scope, we discovered an unprecedented formal N1/N4 cycloaddition of 1,2,4,5-tetrazines with aryl-conjugated enamines, in which the factors that impact this unprecedented change in the reaction mode (N1/N4 vs C3/C6 cycloaddition), origin of the regioselectivity, the substrate scope, and the reaction mechanism were studied in detail. Finally, an expansion of the N1/N4 cycloaddition reactivity to a broader scope of enamines was enabled by the Lewis acid ZnCl2, which overcomes the limitation that non-conjugated enamines were not tolerated in acidic perfluoroalcohol solvents.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2024

Mode of access: World Wide Web

ISBN: 9798380375443Subjects--Topical Terms:

593913
Chemistry.
Subjects--Index Terms:

CycloadditionIndex Terms--Genre/Form:

554714
Electronic books.

Catalysis and New Reactivities of Azadiene Cycloaddition.
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520 $a The Diels−Alder cycloadditions of heterocyclic and acyclic azadienes are powerful reactions widely employed in organic synthesis, medicinal chemistry campaigns, and as tools in chemical biology. However, despite the fact that this reaction has been explored for more than 60 years since its discovery and now countless examples are reported, there has been no general method to catalyze or promote the azadiene cycloaddition reactions and the known approaches are restricted in substrate scope. Moreover, there was only a single mode of cycloaddition (C3/C6 cycloaddition) for the most widely recognized 1,2,4,5-tetrazine and the alternative mode (e.g. N1/N4 cycloaddition) remained unknown. Herein, studies on solvent hydrogen bonding-promoted azadiene Diels−Alder reactions as well as the unprecedented N1/N4 cycloaddition reactivity are summarized.First, the use of perfluoroalcohols (HFIP, TFE, etc.) in the promotion of azadiene cycloadditions recently discovered in the Boger group is generalized through examination of a complete range of azadienes, and other features such as impact on regioselectivity and limitations are also described. Second, in the course of examination of the scope, we discovered an unprecedented formal N1/N4 cycloaddition of 1,2,4,5-tetrazines with aryl-conjugated enamines, in which the factors that impact this unprecedented change in the reaction mode (N1/N4 vs C3/C6 cycloaddition), origin of the regioselectivity, the substrate scope, and the reaction mechanism were studied in detail. Finally, an expansion of the N1/N4 cycloaddition reactivity to a broader scope of enamines was enabled by the Lewis acid ZnCl2, which overcomes the limitation that non-conjugated enamines were not tolerated in acidic perfluoroalcohol solvents.
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