ISSN:0570-0833    

DOI:10.1002/anie.199404891

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractHomogeneous catalysis has been responsible for many major recent developments in synthetic organic chemistry. The combined use of organometallic and coordination chemistry has produced a number of new and powerful synthetic methods for important classes of compounds in general and for optically active substances in particular. For this purpose, complexes with optically active ligands have been used, most of them coordinating through phosphorus. More recent developments have highlighted the use of “nitrogen‐donors”, particularly as they are easily obtained from the “chiral pool”. However, the remarkable achievements in this area have been based on an empirical approach. This article attempts to bridge the gap between the synthetic and the coordination chemist. The first section discusses the rates of formation and dissociation of complexes with nitrogen donors, their relationship to the rates of product formation, and presents the factors which induce homolytic cleavage of MC bonds. It also provides a summary of the main types of organometallic complexes formed by metal centers coordinated to nitrogen donors and their reactivity patterns. The second section highlights the most significant, homogeneously catalyzed reactions involving complexes with nitrogen ligands. Foremost among them are the asymmetric aspects of hydrogenation (particularly those involving boranes as reducing agents), hydrosilylation, cyclopropanations, Diels‐Alder reactions, aldol condensations, alkylation of aldehydes, conjugate addition reactions, Grignard cross‐coupling reactions, allylic alkylations, oxidation reactions, olefin epoxidations, and di‐hydroxy

ISSN:0570-0833    

DOI:10.1002/anie.199404971

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

摘要:

AbstractThe concept of 1,3‐dipolar cycloaddition was developed, starting in the late 1950s, largely by Rolf Huisgen and his students in Munich, and it has led to one of the most versatile methods for the construction of five‐membered ring heterocycles. Although first known only as transient intermediates, nitrile imines have been at the heart of mechanistic studies of this type of cycloaddition reactions. Hundreds of mechanistic papers appeared in 1960s and 1970s; reliable spectroscopic observations were achieved in the early 1980s both at low temperatures and in the gas phase; finally, the first crystalline nitrile imine was reported in 1988. The unusual structures found by X‐ray analyses as well as the facile rearrangements observed experimentally have fostered a new interplay between experiment and theory. The story of nitrile imines, from matrix characterization to stable compounds, nicely illustrates the role that main group elements can play in organic chem

ISSN:0570-0833    

DOI:10.1002/anie.199405271

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199405471

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199405511

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199405551

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199405561

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199405581

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199405591

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.199405621

出版商:Hüthig&Wepf Verlag    

年代:1994

数据来源: WILEY