Catalytic asymmetric synthesis overview

A general overview about advances in the catalytic, asymmetric synthesis of (3-lactams can be found in an article written by Thomas Lectka, whereas a publication by Claudio Palomo discusses reactions of acyl chlorides with imines, including diastereoselectivites and mechanistic insights of the ring closure leading to cis or trans... 

For a general overview of the reduction of imines, see the following (a) Morrison, J.D. (1983) Asymmetric Synthesis, vol. 2, Academic, New York (b) Noyori, R. (1994) Asymmetric Catalysis in Organie Synthesis, John WUey Sons, New York (c) Ojima, I. (2000) Catalytic Asymmetric Synthesis, 2nd edn, John WUey Sons, New York ... 

For general overview of recent advances in this area, see Ojima 1 (ed) (1993) Catalytic Asymmetric Synthesis. VCH, New York Weinherm... 

An overview of the advances in catalytic asymmetric synthesis of /3-lactams was published by Lectka in 2004 °, the diastereoselective formation of /3-lactams from acyl chlorides and imines is discussed by Palomo in 1999 and the influence of solvents in these reactions is summarized by Xu in 2006... 

Asymmetric catalysis is a vital and rapidly growing branch of modern organic chemistry. Within this context, Ti- and Zr-based chiral catalysts have played a pivotal role in the emergence of a myriad of efficient and enantioselective protocols for asymmetric synthesis. In this chapter, a critical overview of enantioselective reactions promoted by chiral Zr-based catalysts is provided. Since an account of this type is most valuable when it provides a context for advances made in a particular area of research, when appropriate, a brief discussion of related catalytic asymmetric reactions promoted by non-Zr-based catalysts is presented as well. 

This article provides a brief overview of several recent total syntheses of natural and unnatural products that have benefited from the use of catalytic asymmetric processes. The article is divided by the type of bond formation that the catalytic enan-tioselective reaction accomplishes (e.g C-C or C-0 bond formation). Emphasis is made on instances where a catalytic asymmetric reaction is utilized at a critical step (or steps) within a total synthesis however, cases where catalytic enantioselective transformations are used to prepare the requisite chiral non-racemic starting materials are also discussed. At the close of the article, two recent total syntheses are examined, where asymmetric catalytic reactions along with a number of other catalyzed processes are the significant driving force behind the successful completion of these efforts (Catalysis-Based Total Syntheses). 

Asymmetric Mannich reactions provide useful routes for the synthesis of optically active p-amino ketones or esters, which are versatile chiral building blocks for the preparation of many nitrogen-containing biologically important compounds [1-6]. While several diastereoselective Mannich reactions with chiral auxiliaries have been reported, very little is known about enantioselective versions. In 1991, Corey et al. reported the first example of the enantioselective synthesis of p-amino acid esters using chiral boron enolates [7]. Yamamoto et al. disclosed enantioselective reactions of imines with ketene silyl acetals using a Bronsted acid-assisted chiral Lewis acid [8]. In all cases, however, stoichiometric amounts of chiral sources were needed. Asymmetric Mannich reactions using small amounts of chiral sources were not reported before 1997. This chapter presents an overview of catalytic asymmetric Mannich reactions. 

Multicomponent reactions (MCRs) are one-pot processes combining three or more substrates simultaneously [1], MCR processes are of great interest, not only because of their atom economy but also for their application in diversity-oriented synthesis and in preparing libraries for the screening of functional molecules. Catalytic asymmetric multicomponent processes are particularly valuable but demanding and only a few examples have been realized so far. Here we provide an overview of this exciting and rapidly growing area. 

This book is presented as a volume of Topics in Organometallic Chemistry, aiming at giving an overview of the chemistry of metallocenes. In particular, in this book we focused on, (i) hydrozirconation and its application to natural product synthesis, (ii) the asymmetric carboalumination reaction, (iii) the cyclization reaction using metallocenes, (iv) catalytic reactions using metallocenes, (v) olefin polymerization and (vi) carbon-carbon bond cleavage reactions using metallocenes. I would like to express my thanks to all contributors to this book. 

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