Journal ArticleDOI
Chiral phosphine lewis bases catalyzed asymmetric aza-Baylis-Hillman reaction of N-sulfonated imines with activated olefins.
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TLDR
An effective bifunctional Lewis base and Bronsted acid phosphine Lewis base system has been disclosed in this catalytic, asymmetric aza-Baylis-Hillman reaction and the mechanistic insight has been investigated by 31P and 1H NMR spectroscopic measurements.Abstract:
In the aza-Baylis-Hillman reaction of N-sulfonated imines (N-arylmethylidene-4-methylbenzenesulfonamides and others) with methyl vinyl ketone, ethyl vinyl ketone, and acrolein, we found that, in the presence of a catalytic amount of chiral phosphine Lewis base such as (R)-2'-diphenylphosphanyl-[1,1']binaphthalenyl-2-ol LB1 (10 mol %) and molecular sieve 4A, the corresponding aza-Baylis-Hillman adducts could be obtained in good yields with good to high ee (70-95% ee) at low temperature (approximately -30 to -20 degrees C) or at room temperature in THF, respectively. In CH2Cl2 upon heating at 40 degrees C, the aza-Baylis-Hillman reaction of N-sulfonated imines with phenyl acrylate or naphthyl acrylate gave the adducts in good to high yields (60-97%) with moderate ee (52-77%). The mechanistic insight has been investigated by 31P and 1H NMR spectroscopic measurements. The key enolate intermediate, which has been stabilized by intramolecular hydrogen bonding, has been observed by 31P and 1H NMR spectroscopy. An effective bifunctional Lewis base and Bronsted acid phosphine Lewis base system has been disclosed in this catalytic, asymmetric aza-Baylis-Hillman reaction.read more
Citations
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Stereoselective synthesis of planar chiral 2,2′-diarylsubstituted ferrocene derivatives as precursors for new 2-phospha[3]ferrocenophanes
TL;DR: Starting from a 1,1′-bis-(SC)-(methoxymethyl)pyrrolidine functionalized ferrocene, an ortholithiation/iodination/chiral auxiliary removal/Suzuki coupling sequence has been achieved as discussed by the authors.
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Efficient Synthesis of 2‐Methyl Derivatives of 1,1′‐Bi(2‐naphthol) and 1,1′‐Bi(2‐phenols)
TL;DR: In this paper, an ultraselective monoderivatisation of 1,1,1′-binaphthol with sulfonylating reagents is described.
Journal ArticleDOI
Privileged chiral catalysts in asymmetric Morita-Baylis-Hillman/aza-Morita-Baylis-Hillman reaction
TL;DR: In this paper, a review summarizes the exciting advances about the design and development of chiral catalysts derived from "privileged structures" and their applications in asymmetric MBH/aza-MBH reaction.
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Effect of Anchimeric Assistance in Addition Reaction of Bifunctional Tertiary Phosphines to Electron‐Deficient Alkenes
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Self-cross-linked quaternary phosphonium based anion exchange membranes: assessing the influence of quaternary phosphonium groups on alkaline stability
TL;DR: In this paper, a series of quaternary phosphonium functionalized poly(aryl ether sulfone)s were successfully synthesized using a new methyl containing monomer via a multi-step process including bromination and alkalization.
References
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Journal ArticleDOI
[(salen)Al]-Mediated, Controlled and Stereoselective Ring-Opening Polymerization of Lactide in Solution and without Solvent: Synthesis of Highly Isotactic Polylactide Stereocopolymers from Racemic d,l-Lactide
TL;DR: Easily accessible [(salen)(iPrO)Al] exerts excellent molecular-weight and stereochemical control in lactide polymerization either in solution or in the absence of solvent.
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Chiral Amine-Catalyzed Asymmetric Baylis−Hillman Reaction: A Reliable Route to Highly Enantiomerically Enriched (α-Methylene-β-hydroxy)esters
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Asymmetric Morita-Baylis-Hillman reactions catalyzed by chiral Brønsted acids.
TL;DR: The Brønsted-acid-catalyzed reaction is the first example of a highly enantioselective asymmetric MBH reaction of cyclohexenone with aldehydes.
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Development of bis-thiourea-type organocatalyst for asymmetric Baylis–Hillman reaction
TL;DR: A chiral bis-thiourea-type organocatalyst 2 developed for the Baylis-Hillman reaction provided a drastic rate enhancement in the case of cyclohexanecarboxaldehyde as discussed by the authors.
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β-Isocupreidine-Catalyzed Asymmetric Baylis−Hillman Reaction of Imines
TL;DR: A mechanistic proposal governed by hydrogen bonding is presented to give (S)-enriched N-protected-alpha-methylene-beta-amino acid esters, which shows the opposite enantioselectivity to the corresponding aldehydes.