Direct Organocatalytic Asymmetric Approach to Baylis–Hillman‐Type Products Through a Push–Pull Dienamine Platform

Ramachary, Dhevalapally B.; Ramakumar, Kinthada

doi:10.1002/ejoc.201100075

Cited by 26 publications

(11 citation statements)

References 42 publications

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“…discovered the first process for the preparation of MBH reaction products of Hagemann′s esters and β‐nitro styrenes. Though in most examples only low diastereoselectivity together with moderate yields and enantioselectivities were achieved, this method could represent a starting point for further developments in this area (Scheme ) 113…”

Section: Morita–baylis–hillman Reactionsmentioning

confidence: 99%

“…Though in most examples only low diastereoselectivity together with moderate yields and enantioselectivities were achieved, this method could represent a starting point for further developments in this area (Scheme 52). [113] With regard to ecological considerations the execution of MBH reactions in aqueous media via phase-transfer catalysis is a very interesting research topic. Coelho et al demonstrated such a method with a phosphorus-free imidazole-catalyst 117.…”

Section: Morita-baylis-hillman Reactionsmentioning

confidence: 99%

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Recent Advances in Organocatalytic Methods for Asymmetric CC Bond Formation

Scheffler

Mahrwald

2013

Chemistry A European J

197

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Beyond a doubt organocatalysis belongs to the most exciting and innovative chapters of organic chemistry today. Organocatalysis has emerged not only as a complement to metal-catalyzed reactions and to biocatalysis over the last decade, but also provides new asymmetric organocatalyzed reactions that cannot be accomplished by metal- or biocatalyzed reactions so far. A large number of organocatalytic processes are already well established in organic synthesis. Nevertheless, the number of publications in this field is still on the increase; new important results are produced constantly. This review gives a detailed overview of the latest developments and main streams in organocatalyzed asymmetric CC bond formation processes of the last three years. It is intended to outline the most important current findings focused on especially new synthetic methodologies.

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Section: Morita–baylis–hillman Reactionsmentioning

confidence: 99%

Section: Morita-baylis-hillman Reactionsmentioning

confidence: 99%

Recent Advances in Organocatalytic Methods for Asymmetric CC Bond Formation

Scheffler

Mahrwald

2013

Chemistry A European J

197

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“…In 2011, Ramachary et al reported a new, metal‐free technology for the synthesis of substituted 2‐alkyl‐3‐(1‐aryl‐2‐nitroethyl)‐4‐oxocyclohex‐2‐enecarboxylates by use of a Baylis–Hillman‐type reaction and the push‐pull dienamine platform 31. This is the first report involving asymmetric coupling between α,β‐unsaturated ketones and β‐nitrostyrenes at the enone α‐position with the aid of dienamine catalysis.…”

Section: Ramachary Dienamines (Push‐pull Dienamines) – In Situ Genmentioning

confidence: 99%

“…This is the first report involving asymmetric coupling between α,β‐unsaturated ketones and β‐nitrostyrenes at the enone α‐position with the aid of dienamine catalysis. The reaction between the Hagemann's ester 121b (Scheme ) and the nitro olefin 32c in the presence of the amine 152 as catalyst furnished the BH‐type products 153 and 154 via the transition states 155 and 156 in 61 % yield, 2.1:1 dr and 84 and 40 % enantiomeric excess respectively 31…”

Section: Ramachary Dienamines (Push‐pull Dienamines) – In Situ Genmentioning

confidence: 99%

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Dienamine Catalysis: An Emerging Technology in Organic Synthesis

2011

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High-yielding asymmetric synthesis of bioactive molecules with the aid of mild catalysis is an efficient approach in reaction engineering. In the early days, synthetic chemists mainly focused on the synthesis of complex molecules, but not much on reaction efficiency and eco-friendly conditions. Recent investigations have been directed towards the development of atom economy and of eco-friendly and enantioselective syn-

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The Catalytic, Enantioselective Michael Reaction

et al. 2016

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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.

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Direct Organocatalytic Asymmetric Approach to Baylis–Hillman‐Type Products Through a Push–Pull Dienamine Platform

Abstract: A general process for the asymmetric synthesis of highly substituted 3-alkyl-Hagemann's esters was achieved for the first time through organocatalytic Michael or Baylis-Hillman-type (BH-type) reaction of Hagemann's esters with β-nitrostyrenes

Cited by 26 publications

References 42 publications

Recent Advances in Organocatalytic Methods for Asymmetric CC Bond Formation

Recent Advances in Organocatalytic Methods for Asymmetric CC Bond Formation

Dienamine Catalysis: An Emerging Technology in Organic Synthesis

The Catalytic, Enantioselective Michael Reaction

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