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Journal ArticleDOI

Primary β-Amino Acid Salt-catalyzed Asymmetric Michael Addition of Benzoylacetates to Cyclic Enones and Its Application for the Synthesis of Enantioenriched 1,5-Diketones

02 Feb 2013-Chemistry Letters (The Chemical Society of Japan 公益社団法人 日本化学会)-Vol. 42, Iss: 2, pp 180-182
TL;DR: In this article, the asymmetric addition of benzoylacetates to cyclic enones was successfully carried out by using a primary β-amino acid salt catalyst, and the reactions proceeded under mild reaction condition.
Abstract: The asymmetric Michael addition of benzoylacetates to cyclic enones was successfully carried out by using a primary β-amino acid salt catalyst. The reactions proceeded under mild reaction condition...
Citations
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Journal ArticleDOI
TL;DR: This review provides comprehensive and critical information on the enantioselective 1,4-conjugate addition of nonorganometallic (soft) nucleophiles and their importance in synthetic applications.
Abstract: The metal-catalyzed asymmetric conjugate addition (ACA) reaction has emerged as a general and powerful approach for the construction of optically active compounds and is among the most significant and useful reactions in synthetic organic chemistry In recent years, great progress has been made in this area with the use of various chiral metal complexes based on different chiral ligands This review provides comprehensive and critical information on the enantioselective 1,4-conjugate addition of nonorganometallic (soft) nucleophiles and their importance in synthetic applications The literature is covered from the last 10 years, and a number of examples from before 2007 are included as background information The review is divided into multiple parts according to the type of nucleophile involved in the reaction (such as C-, B-, O-, N-, S-, P-, and Si-centered nucleophiles) and metal catalyst systems used

187 citations

Journal ArticleDOI
TL;DR: The allylation reaction and generation of a chiral quaternary carbon stereocenter proceeded smoothly to produce α,α-disubstituted β-ketoesters in high yields (91-99%) with high enantioselectivities (90-99% ee).
Abstract: Enantioselective α-allylation of α-substituted β-ketoesters with simple allyl alcohols was successfully performed by synergistic catalysis with the catalyst combination of a chiral primary amino acid and an achiral palladium complex without additional promotors like acids or bases. The allylation reaction and generation of a chiral quaternary carbon stereocenter proceeded smoothly to produce α,α-disubstituted β-ketoesters in high yields (91–99%) with high enantioselectivities (90–99% ee).

23 citations

Journal ArticleDOI
TL;DR: The versatility of the optimum catalyst with the (Trp)2-( Leu-Leu-Aib)3 sequence was demonstrated by applying it to other organocatalytic reactions such as the Michael addition of malonates to α,β-unsaturated ketones and a three-component, sequential reaction with methacrolein.

18 citations

Reference EntryDOI
TL;DR: This chapter describes different catalytic systems and methods developed for achieving enantioselective Michael reactions through the end of 2012, including a detailed mechanistic explanation of the different generic modes of substrate activation operating with each type of catalyst and their associated stereochemical aspects.
Abstract: The catalytic enantioselective Michael reaction is the conjugate addition of a resonance-stabilized carbanion to an electron-poor olefin (an αβ-unsaturated carbonyl compound or a related derivative) mediated by substoichiometric amounts of a chiral catalyst that enables stereocontrol in the newly generated stereocenter(s). This reaction allows the direct enantioselective construction of substituted 1,5-dicarbonyl compounds or related architectures through the appropriate selection of the enolizable carbonyl compound employed as pronucleophile and the Michael acceptor. A variety of catalyst architectures have been described that make it possible to carry out this reaction with superior levels of chemical efficiency and high enantio- and stereocontrol, and also under conditions that tolerate a wide variety of functional groups. Both transition metal catalysis and organocatalysis have been employed as methodological approaches for carrying out this reaction in an enantioselective manner. This chapter describes different catalytic systems and methods developed for achieving enantioselective Michael reactions through the end of 2012, including a detailed mechanistic explanation of the different generic modes of substrate activation operating with each type of catalyst and their associated stereochemical aspects. The intention is to provide researchers interested in applying this methodology to their own synthetic strategies with a suitable starting point for identifying an efficient synthetic approach. In addition, the preparation of selected catalysts that are excellent for a particular pairing of substrates in this reaction, together with practical experimental protocols are described and some examples in which these methodologies have been applied to total synthesis have been included. This chapter is limited exclusively to those examples in which the final Michael addition product is obtained after protonation of the conjugate addition intermediate and therefore, tandem, domino, or cascade processes initiated by Michael reactions lie outside the scope of this work. Supplemental references are provided for articles published after the 2012 cut-off date through the first half of 2015. Keywords: asymmetric synthesis; carbanions; catalysis; conjugate addition; Michael reaction

15 citations

Journal ArticleDOI
TL;DR: In this article, a mechanistic study was carried out for the asymmetric Michael addition reaction of malonates to enones catalyzed by a primary amino acid lithium salt to elucidate the origin of asymmetric induction.

12 citations

References
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Journal ArticleDOI
TL;DR: The diverse examples show that in recent years organocatalysis has developed within organic chemistry into its own subdiscipline, whose "Golden Age" has already dawned.
Abstract: The term "organocatalysis" describes the acceleration of chemical reactions through the addition of a substoichiometric quantity of an organic compound. The interest in this field has increased spectacularly in the last few years as result of both the novelty of the concept and, more importantly, the fact that the efficiency and selectivity of many organocatalytic reactions meet the standards of established organic reactions. Organocatalytic reactions are becoming powerful tools in the construction of complex molecular skeletons. The diverse examples show that in recent years organocatalysis has developed within organic chemistry into its own subdiscipline, whose "Golden Age" has already dawned.

2,279 citations

Journal ArticleDOI
17 Sep 2008-Nature
TL;DR: My opinion on why the field of organocatalysis has blossomed so dramatically over the past decade is presented.
Abstract: The use of small organic molecules as catalysts has been known for more than a century. But only in the past decade has organocatalysis become a thriving area of general concepts and widely applicable asymmetric reactions. Here I present my opinion on why the field of organocatalysis has blossomed so dramatically over the past decade.

1,863 citations

Journal ArticleDOI
TL;DR: Recent progress in the field of asymmetric organocatalytic 1,4-conjugate addition reactions, regarded as belonging among the more synthetically important carbon-carbon bond-forming reactions, is described in this article.

1,022 citations

Journal ArticleDOI
TL;DR: In this paper, the asymmetric conjugate addition of various carbon and heteroatom nucleophiles to nitroalkenes as a tool for the construction of highly functionalized synthetic building blocks is presented.

756 citations

Journal ArticleDOI
TL;DR: An overview of the most important developments and concepts of this flourishing area of catalysis organized by the type of nucleophile involved in the process is reported.
Abstract: The asymmetric organocatalytic conjugate addition of nucleophiles to Michael acceptors is reviewed. Herein an overview of the most important developments and concepts of this flourishing area of catalysis organized by the type of nucleophile involved in the process is reported.

751 citations