Journal ArticleDOI
Multivalency as a Key Factor for High Activity of Selective Supported Organocatalysts for the Baylis–Hillman Reaction
Kerem Goren,Jeny Karabline-Kuks,Yael Shiloni,Einav Barak-Kulbak,Scott J. Miller,Moshe Portnoy +5 more
TLDR
The polystyrene-supported N-alkylimidazole-based dendritic catalysts for the Baylis-Hillman reaction exhibit one of the strongest beneficial effects of multivalent architecture ever reported for an organocatalyst.Abstract:
The polystyrene-supported N-alkylimidazole-based dendritic catalysts for the Baylis-Hillman reaction exhibit one of the strongest beneficial effects of multivalent architecture ever reported for an organocatalyst. The yields in the model reaction of methyl vinyl ketone with p-nitrobenzaldehyde are more than tripled when a non-dendritic catalyst is replaced by a second- or third-generation analogue. Moreover, the reaction of the less active substrates will not occur with the non-dendritic catalyst and will proceed to a significant extent only with the analogous catalysts of higher generations. A substantial additional enhancement of the reaction yield could be achieved by increasing the content of water in the reaction solvent. The plausible cause of the dendritic effect is the assistance of the second, nearby imidazole moiety in the presumably rate-determining proton transfer in the intermediate adduct, after the first imidazole unit induced the formation of the new carbon-carbon bond.read more
Citations
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Journal ArticleDOI
Design of peptide-containing N5-unmodified neutral flavins that catalyze aerobic oxygenations.
Yukihiro Arakawa,Ken Yamanomoto,Hazuki Kita,Keiji Minagawa,Masami Tanaka,Naoki Haraguchi,Shinichi Itsuno,Yasushi Imada +7 more
TL;DR: The first flavoenzyme-mimetic aerobic oxygenations catalyzed by N5-unmodified neutral flavin were realized with flavopeptides (Fl-Pep) rationally designed by computational calculations.
Journal ArticleDOI
Multivalent polyglycerol supported imidazolidin-4-one organocatalysts for enantioselective Friedel-Crafts alkylations.
TL;DR: The first immobilization of a MacMillan’s first generation organocatalyst onto dendritic support on the basis of modified tyrosine-based imidazolidin-4-one is described.
Journal ArticleDOI
Polyvalent Catalysts Operating on Polyvalent Substrates: A Model for Surface-Controlled Reactivity.
Craig S. McKay,M. G. Finn +1 more
TL;DR: These findings constitute a rare experimental example of an underappreciated phenomenon in biological and chemical systems that are organized on interacting surfaces that are sensitive to the density of functional groups on each dendrimer, and insensitive to factors that promote or inhibit nonspecific particle aggregation.
Journal ArticleDOI
Baylis–Hillman Reaction: In Situ Generated Isoquinolinium Species as Excellent Electrophiles for Coupling with Alkyl Acrylates and Acrylonitrile
Journal ArticleDOI
Novel poly(2-oxazoline)s with pendant L-prolinamide moieties as efficient organocatalysts for direct asymmetric aldol reaction
TL;DR: Based on circular dichroism spectrum analysis, the enhancement in catalytic activity is probably related to the conformational changes of the pseudo-peptide scaffold of poly(2-oxazoline)s.
References
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Synthetic Multivalent Ligands as Probes of Signal Transduction
TL;DR: This Review focuses on the use of synthetic multivalent ligands to characterize receptor function through chemical synthesis to address the role of receptor assembly in signal transduction.
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Recent contributions from the Baylis-Hillman reaction to organic chemistry.
TL;DR: Acyclic activated alkenes/ alkynes and Asymmetric Baylis-Hillman Reaction: Earlier Developments 5495.
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Multivalency and cooperativity in supramolecular chemistry.
TL;DR: This Account focuses on the application of multivalency to supramolecular chemistry in particular and the nanosciences in general.
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Recent advances in organocatalytic asymmetric Morita-Baylis-Hillman/aza-Morita-Baylis-Hillman reactions.
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The Baylis–Hillman reaction: a novel source of attraction, opportunities, and challenges in synthetic chemistry
TL;DR: The Baylis-Hillman reaction is a successful, useful, and atom-economical carbon-carbon bond forming reaction, which has grown from an obscure level to the level of high synthetic popularity due to its operational simplicity and also due to the enormous applications of the Baylis/Hillman adducts in organic synthesis.