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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Book ChapterDOI
Morita–Baylis–Hillman, Vinylogous Morita–Baylis–Hillman, and Rauhut–Currier Reactions
Journal ArticleDOI
2‐(1S)‐Camphanoyloxy‐2′‐phosphanylbiphenyl Ligands – Synthesis, Structure, and Preliminary Tests in Transition‐Metal Catalysis
Piotr Wawrzyniak,Markus K. Kindermann,Gabriele Thede,Richard Thede,Peter G. Jones,Stephan Enthaler,Katrin Junge,Matthias Beller,Joachim Heinicke +8 more
TL;DR: In this article, the (1S)-camphanoyloxy-biphenylphosphanes 3a-c were shown to be 1:1 mixtures of diastereomers with low barrier for interconversion by rotation around the C-C axis.
Book ChapterDOI
6.9 C–C Bond Formation: (aza) Morita–Baylis–Hillman Reaction
Hiroaki Sasai,Shinobu Takizawa +1 more
TL;DR: This chapter has described recent mechanistic insights and advances in the enantioselective MBH and aza-MBH reactions.
Journal ArticleDOI
Construction of α,α-disubstituted α-Amino Acid Derivatives via aza-Morita-Baylis-Hillman Reactions of 2-Aminoacrylates with Activated Olefins
Hou-Ze Gui,Harish Jangra,Ben Mao,Tian‐Yu Wang,Heng Yi,Qin Xu,Yin Wei,Hendrik Zipse,Min Shi,Min Shi,Min Shi +10 more
TL;DR: The kinetic profiles and calculated methyl anion affinity (MAA) values were employed to rationalize the reactivities of different Michael acceptors used in the Reaction of 2‐aminoacrylates with activated olefins.
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.
Journal ArticleDOI
Chiral Amine-Catalyzed Asymmetric Baylis−Hillman Reaction: A Reliable Route to Highly Enantiomerically Enriched (α-Methylene-β-hydroxy)esters
Journal ArticleDOI
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.
Journal ArticleDOI
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.
Journal ArticleDOI
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.