Asymmetric Baylis Hillman Reaction Research Articles

Asymmetric Baylis–Hillman reaction catalyzed by pyrrolidine based organocatalyst

An asymmetric Baylis–Hillman reaction protocol has been developed using a chiral pyrrolidine based organocatalyst. The catalytic loading works well with a wide range of aromatic aldehydes to afford the corresponding β-hydroxy acrylate with high enantioselectivity up to 100% with excellent yields. The organocatalyst shows excellent enantioselectivity with 10 mol% of catalytic loading at room temperature condition.

ChemInform Abstract: Methods for the Synthesis of Chiral Sulfur Heterocycles and Their Application in the Asymmetric Baylis—Hillman Reactions.

AbstractDimesylates of chiral diols cyclize in the presence of sodium sulfide to provide sulfur heterocycles (III) and (VII).

Methods for the synthesis of chiral sulfur heterocycles and their application in the asymmetric Baylis–Hillman reactions

Enantiomerically pure (2S,6S)-2,6-diphenyltetrahydro-2H-thiopyran, (2S)-2-phenyltetrahydro thiophene, and (2S)-2-phenyltetrahydro-2H-thiopyran were prepared in 70–72% yields and with 86–99% ee via cyclization of the corresponding dimesylate in an SN2 cyclization reaction using sodium sulfide nonahydrate. The results on the application of various chiral sulfides in asymmetric Baylis–Hillman reactions are also described.

ChemInform Abstract: Catalytic Asymmetric Baylis—Hillman Reactions and Surroundings

AbstractReview: 150 refs.

Asymmetric Total Synthesis of 6-Tuliposide B and Its Biological Activities against Tulip Pathogenic Fungi

The structure-activity relationship was investigated to evaluate the antifungal activities of tuliposides and tulipalins against tulip pathogenic fungi. 6-Tuliposide B was effectively synthesized via the asymmetric Baylis-Hillman reaction. Tuliposides and tulipalins showed antifungal activities against most of the strains tested at high concentrations (2.5 mM), while Botrytis tulipae was resistant to tuliposides. Tulipalin formation was involved in the antifungal activity, tulipalin A showed higher inhibitory activity than 6-tuliposide B and tulipalin B. Both the tuliposides and tulipalins showed pigment-inducing activity against Gibberella zeae and inhibitory activity against Fusarium oxysporum f. sp tulipae. These activities were induced at a much lower concentration (0.05 mM) than the antifungal MIC values.

ChemInform Abstract: Design and Synthesis of Bistereogenic Chiral Ionic Liquids and Their Use as Solvents for Asymmetric Baylis—Hillman Reactions.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Asymmetric Baylis-Hillman Reaction: An Enchanting Expedition

The development of new strategies for realizing the asymmetricBaylis-Hillman reaction remains at the forefront of researchinto this important organic reaction. This review gives a comprehensiveaccount of the work that has emanated from our group on the asymmetricBaylis-Hillman reaction. Herein, the use of homochiralelectrophiles, Michael acceptors, and bases and double asymmetricinduction protocols as tools for the asymmetric Baylis-Hillmanreaction is discussed. The account also covers the application ofsuch protocols in natural product synthesis. 1 Introduction 2 Asymmetric Baylis-Hillman Reaction: A Personal Account 2.1 Homochiral Electrophiles 2.1.1 Sugar-Derived Aldehydes 2.1.2 Chiral 2,3-Epoxy Aldehydes 2.2 Homochiral Michael Acceptors 2.2.1 TADDOL Acrylates 2.2.2 Sugar-Derived Acrylates 2.2.3 A Sugar-Derived Lactone 2.3 Homochiral Catalysts 2.3.1 N-Methylprolinol as the ChiralCatalyst 2.3.2 Other Chiral Catalysts 2.4 Double Asymmetric Induction 2.5 Applications 2.5.1 α-Methylene-β-hydroxylactones via anIntramolecular Baylis-Hillman Reaction 2.5.2 Synthesis of Syributins 2.5.3 Sequential Baylis-Hillman Reaction and Ring-Closing Metathesisas a Protocol for Sugar-Linked α,β-Unsaturated γ-LactoneLibrary Generation 2.5.4 Synthesis of Non-natural Higher-Carbon Sugars 3 Conclusion

Design and synthesis of bistereogenic chiral ionic liquids and their use as solvents for asymmetric Baylis–Hillman reactions

Three novel chiral ionic liquids (CILs) containing two chiral centers in the side chain bonded to the 2-position of the imidazolium cation and different anions have been synthesized, characterized and used as chiral solvents for asymmetric Baylis-Hillman (BH) reactions; good yields and fair enantioselectivities were obtained.

Nonenzymatic Acylative Kinetic Resolution of Baylis−Hillman Adducts

The first efficient nonenzymatic acylative kinetic resolution of Baylis-Hillman adducts is reported. Chiral pyridine catalyst 1a and an optimized analogue 1e are capable of promoting the synthetically useful enantioselective acylation (the efficiency of which is outstanding for sp(2)-sp(2) carbinol substrates, s = 3.5-13.1, ee up to 97%) of Baylis-Hillman adducts derived from recalcitrant precursors which are currently difficult to synthesize utilizing benchmark asymmetric Baylis-Hillman reaction catalyst technology. A novel one-pot synthesis-kinetic resolution process involving a DBU-catalyzed Baylis-Hillman reaction and subsequent 1e/DBU-mediated enantioselective acylation has also been developed.

β‐Isocupreidine‐Catalyzed Asymmetric Baylis—Hillman Reactions

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Asymmetric Baylis—Hillman Reactions Promoted by Chiral Imidazolines.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Asymmetric Baylis-Hillman Reactions Catalyzed by Chiral Imidazolines

Chiral imidazolines are used to generate enantioenriched Baylis-Hillman products in the reaction of electron-deficient aromatic aldehydes with acrylates or alkyl vinyl ketones. The reaction generates the products in moderate to very good yield and in moderate enantioselectivities. Reactions without solvent were found to be optimal for acrylates, while the corresponding reaction with ketones is best run in toluene.

Asymmetric Baylis—Hillman Reaction: Use of Novel Chiral Aldehydes as Electrophiles, Chiral Base Catalysts and Auxiliaries

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Asymmetric Baylis–Hillman Reactions Promoted by Chiral Imidazolines

The coupling of electrophiles with activated alkenes by using tertiary amines or phosphines is generally known as the Baylis-Hillman reaction. It is a useful and atom-economical carbon-carbon bond-forming reaction that generates multifunctionalized products. This reaction is notoriously slow; yields are often low and substrate-dependent. The asymmetric reaction is still limited especially for unactivated olefins such as acrylates. Imidazolines have been developed as ligands in metal-catalyzed reactions and have also been used as privileged structures in diversity-oriented synthesis. A series of novel chiral imidazolines were prepared and used to develop asymmetric Baylis-Hillman reactions. These imidazolines promote the reactions of various aromatic aldehydes with unactivated acrylates. Enantiomeric excesses of up to 60% and high yields were obtained by using stoichiometric amounts of the promoter. Furthermore, the imidazolines are also suitable promoters for the reactions between aromatic aldehydes and alkyl vinyl ketones. Enantiomeric excesses of up to 78% and high yields were obtained with 50 mol % of an imidazoline with a chiral methylnaphthyl group. These chiral imidazolines are easily prepared from commercially available amino alcohols and can be easily recovered for reuse without loss of product enantioselectivity.

Chiral Activated Alkenes Induced Asymmetric Baylis—Hillman Reaction in Me3N/H2O/Solvent Medium.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

β‐Isocupreidine—Hexafluoroisopropyl Acrylate Method for Asymmetric Baylis—Hillman Reactions.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Asymmetric Baylis-Hillman Reaction: Use of Novel Chiral Aldehydes as Electrophiles, Chiral Base Catalysts and Auxilliaries&#

Asymmetric Baylis-Hillman Reaction: Use of Novel Chiral Aldehydes as Electrophiles, Chiral Base Catalysts and Auxilliaries&#

Chiral activated alkenes induced asymmetric Baylis–Hillman reaction in Me3N/H2O/solvent medium

AbstractChiral‐activated alkenes, L‐menthyl acrylate and (+)‐N‐α‐phenylethyl acrylamide, induced asymmetric Baylis–Hillman reaction of aromatic aldehydes was realized at 25°C for 7 days in Me3N/H2O/solvent homogeneous medium. The corresponding Baylis–Hillman adducts were obtained in good chemical yield with moderate to excellent diastereoselectivity (up to 99% de). © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:317–321, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20209

.BETA.-Isocupreidine-Catalyzed Asymmetric Baylis-Hillman Reactions

Highly enantioselective asymmetric Baylis-Hillman reactions employing (3R, 8R, 9S) -10, 11-dihydro-3, 9-epoxy-6'-hydroxy-cinchonane, β-isocupreidine (β-ICD), as a chiral amine catalyst and 1, 1, 1, 3, 3, 3-hexafluoroisopropyl acrylate (HFIPA) as an activated alkene are described for aldehydes including chiral N-Boc-α-amino aldehydes and aromatic N-diphenylphosphinoyl imines. The key features of this β-ICD-HFIPA method and a plausible reaction mechanism governed by hydrogen bonding are presented.

Synthesis of an Enantiocomplementary Catalyst of β‐Isocupreidine (β‐ICD) from Quinine

AbstractCompound 20, a pseudoenantiomer of β‐isocupreidine (β‐ICD), was synthesized from quinine employing a Barton reaction of nitrosyl ester 13 and acid‐catalyzed cyclization of carbinol 18 as key steps. The Baylis–Hillman reaction of benzaldehyde, p‐nitrobenzaldehyde, and hydrocinnamaldehyde with 1,1,1,3,3,3‐hexafluoroisopropyl acrylate (HFIPA) using 20 as a chiral amine catalyst was found to give the corresponding S‐enriched adducts in high optical purity (>91% ee) in contrast to the β‐ICD‐catalyzed reaction which affords R‐enriched adducts. This result suggests that compound 20 can serve as an enantiocomplementary catalyst of β‐ICD in the asymmetric Baylis–Hillman reaction of aldehydes with HFIPA.