1.

Record Nr.

UNINA9910298612803321

Autore

Zhang Shaoguang

Titolo

The Chemistry of Zirconacycles and 2,6-Diazasemibullvalenes : Synthesis, Structures, Reactions, and Applications in the Synthesis of Novel N-Heterocycles / / by Shaoguang Zhang

Pubbl/distr/stampa

Berlin, Heidelberg : , : Springer Berlin Heidelberg : , : Imprint : Springer, , 2015

ISBN

3-662-45021-6

Edizione

[1st ed. 2015.]

Descrizione fisica

1 online resource (182 p.)

Collana

Springer Theses, Recognizing Outstanding Ph.D. Research, , 2190-5053

Disciplina

547.05

Soggetti

Organometallic chemistry

Chemistry, Physical and theoretical

Crystallography

Organometallic Chemistry

Physical Chemistry

Theoretical and Computational Chemistry

Crystallography and Scattering Methods

Lingua di pubblicazione

Inglese

Formato

Materiale a stampa

Livello bibliografico

Monografia

Note generali

"Doctoral Thesis accepted by Peking University, Beijing, China."

Nota di bibliografia

Includes bibliographical references at the end of each chapters.

Nota di contenuto

Introduction to Zirconacycle Chemistry -- Zirconocene-Mediated Cyclization of Bis(alkynyl)silanes and Nitriles: Synthesis of N-Heterocycles and Isolation, Characterization and Synthetic Application of Zr/Si-containing Reactive Intermediates -- Bulky-Nitrile Coordination Induced Skeleton Rearrangement of Zr/Si-containing Metallacycles and Selective Synthesis of 5-Azaindoles -- Introduction to Semibullvalenes and Azasemibullvalenes -- 2,6-Diazasemibullvalenes: Synthesis, Structure, Theoretical Analysis and Computational Chemistry -- 2,6-Diazasemibullvalenes: Reaction Chemistry and Synthetic Application.

Sommario/riassunto

In this thesis, the author introduces two strategies used to construct various types of N-heterocycles, based on the chemistry of zirconacycles and 2,6-diazasemibullvalenes. In the first part, the author presents the development of multi-component cyclization of a



zirconacyclobutene-silacyclobutene fused compound, nitriles and unsaturated compounds. These reactions provide synthetically useful methodology for various N-heterocycles such as 3-acyl pyrrole, pyrrolo[3,2-d]pyridazine and dihydropyrroloazepine, which are all difficult to synthesize by other means. The isolation and characterization of the key three-fused-ring Zr/Si-containing intermediates are also described in detail. These results show that the zirconacyclobutene-silacyclobutene fused compound behaves as a “chemical transformer” upon treatment with various substrates via the “coordination-induced skeleton rearrangement” mechanism. In the second part, the author demonstrates the synthesis and isolation of a series of 2,6-diazasemibullvalenes (NSBVs) from the reaction of 1,4-dilithio-1,3-dienes and nitriles, highlighting the significant progress made for the first time in this work: (1) determination of X-ray crystal structure of a substituted 2,6-diazasemibullvalene; (2) measurement of the activation barrier of its rapid intramolecular aza-Cope rearrangement in solution; (3) exploration of several reaction types of NSBV with diverse ring-expansion products and “bowl-shape” or “cage-shape” N-containing polycyclic skeletons; (4) demonstration of the localized structure as the predominant form and the homoaromatic delocalized structure as a minor component in the equilibrium using theoretical analysis. Based on well-founded results, this work sheds new light on this controversial topic.