Morita Baylis Hillman Acetates Research Articles

Asymmetric synthesis of pyrano[2,3-c]pyrazoles via a cascade reaction between Morita–Baylis–Hillman acetates of nitroalkenes and pyrazolones

The first organocatalytic enantioselective cascade reaction of Morita–Baylis–Hillman acetates of nitroalkenes with pyrazolones has been developed. With 20 mol% of chiral tertiary-amine squaramide, 1,4,5,6-tetrahydropyrano[2,3-c]pyrazoles were afforded in moderate yields (up to 71%) with excellent stereoselectivities (up to>99:1 dr and up to 98% ee).

ChemInform Abstract: Synthesis of Tetrahydropyridines from Morita—Baylis—Hillman Acetates of α,β‐Unsaturated Aldehydes via an Intramolecular 1,6‐Conjugate Addition.

ChemInform Abstract: Synthesis of Tetrahydropyridines from Morita—Baylis—Hillman Acetates of α,β‐Unsaturated Aldehydes via an Intramolecular 1,6‐Conjugate Addition.

ChemInform Abstract: Enantioselective Allylic Amination of Morita—Baylis—Hillman Acetates Catalyzed by Chiral Thiourea‐Phosphine.

The enantioselective allylic amination of Morita-Baylis-Hillman acetates catalyzed by chiral cyclohexane-based thiourea-phosphine catalysts was investigated. In the presence of 20 mol% rosin-derived thiourea-phosphine 3j, the chiral amines were obtained in up to 88% yield and up to 85% ee.

ChemInform Abstract: Synthesis of 3,4,5‐Trisubstituted Isoxazoles from Morita—Baylis—Hillman Acetates by an NaNO2/I2‐Mediated Domino Reaction.

AbstractAddition of NaNO2 to the starting acetates under conditions A) leads to formation of the required highly functionalized isoxazole derivatives (mechanism).

Synthesis of Tetrahydropyridines from Morita–Baylis–Hillman Acetates of α,β‐Unsaturated Aldehydes Via an Intramolecular 1,6‐Conjugate Addition

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Synthesis of Trisubstituted Isoxazoles from Morita–Baylis–Hillman Acetates

Synthesis of Trisubstituted Isoxazoles from Morita–Baylis–Hillman Acetates

Synthesis of 3,4,5‐Trisubstituted Isoxazoles from Morita–Baylis–Hillman Acetates by an NaNO2/I2‐Mediated Domino Reaction

AbstractAn efficient NaNO2/I2‐mediated one‐pot transformation of Morita–Baylis–Hillman (MBH) acetates into alkyl 3‐nitro‐5‐(aryl/alkyl)isoxazole‐4‐carboxylates is described. In a cascade event, initial Michael addition of NaNO2 to the MBH acetate furnishes the allylnitro intermediate which undergoes I2‐catalyzed oxidative α‐CH nitration of the nitromethyl subunit followed by [3+2] cycloaddition to afford the title compounds. Structural elaborations of these highly substituted isoxazoles by SNAr reactions and hydrogenolysis allows access to useful products.

Synthesis of Ramirez ylides from Morita–Baylis–Hillman adducts of α-bromocinnamaldehyde: an intramolecular 1,6-conjugate addition of phosphorus ylide

Ramirez ylides were synthesized in good yields from Morita–Baylis–Hillman acetates of α-bromocinnamaldehyde and phosphines in a one-pot reaction. The Ramirez ylides were formed by a novel intramolecular 1,6-conjugate addition of phosphorus ylide as a key step.

ChemInform Abstract: Construction of Dispirocyclohexanes via Amine‐Catalyzed [2 + 2 + 2] Annulations of Morita—Baylis—Hillman Acetates with Exocyclic Alkenes.

AbstractThe presented method offers a novel and efficient one‐step procedure for the construction of complex architectures bearing a dispirocyclohexane motif.

ChemInform Abstract: Tunable Base‐Controlled Regioselective Cascade Reaction of 2‐Mercaptobenzimidazole with Morita—Baylis—Hillman Acetates of Nitroalkenes.

Two series of heterocyclic compounds, thiazolo[3,2-a]benzimidazoles and benzimidazo[2,1-b]-1,3-thiazines, were synthesized by the tunable base-controlled regioselective cascade reaction of 2-mercaptobenzimidazole with Morita–Baylis–Hillman acetates of nitroalkenes in good yields with high regioselectivities.

ChemInform Abstract: Chiral Phosphines in Nucleophilic Organocatalysis

AbstractReview: 117 refs.

Probing the mechanism of allylic substitution of Morita-Baylis-Hillman acetates (MBHAs) by using the silyl phosphonite paradigm: scope and applications of a versatile transformation.

A P-C bond-forming reaction between silyl phosphonites and Morita-Baylis-Hillman acetates (MBHAs) is explored as a general alternative towards medicinally relevant β-carboxyphosphinic structural motifs. Conversion rates of diversely substituted MBHAs to phosphinic acids 9 or 14 that were recorded by using (31) P NMR spectroscopy revealed unexpected reactivity differences between ester and nitrile derivatives. These kinetic profiles and DFT calculations support a mechanistic scenario in which observed differences can be explained from the "lateness" of transition states. In addition, we provide experimental evidence suggesting that enolates due to initial P-Michael addition are not formed. Based on the proposed mechanistic scenario in conjunction with DFT calculations, an interpretation of the E/Z stereoselectivity differences between ester and nitriles is proposed. Synthetic opportunities stemming from this transformation are presented, which deal with the preparation of several synthetically capricious phosphinic building blocks, whose access through the classical P-Michael synthetic route is not straightforward.

One-pot regioselective synthesis of functionalized and fused furans from Morita–Baylis–Hillman and Rauhut–Currier adducts of nitroalkenes

Functionalized and fused furans were synthesized by a one-pot regioselective cascade reaction from Morita–Baylis–Hillman acetates and Rauhut–Currier adducts of nitroalkenes.

ChemInform Abstract: Novel [4 + 2]‐Benzannulation to Access Substituted Benzenes and Polycyclic Aromatic and Benzene‐Fused Heteroaromatic Compounds.

A common [4 + 2]-benzannulation of Morita–Baylis–Hillman acetates of acetylenic aldehydes with boronic acids has been developed for the synthesis of aromatic and heteroaromatic compounds through tandem allylic substitution/hydroarylative cycloisomerization process. This method provides a facile and general route to substituted benzenes, naphthalenes, other polycyclic aromatics, and various benzene-fused heteroaromatic compounds such as benzofuran, benzothiophene, indole, and carbazoles.

Chiral phosphines in nucleophilic organocatalysis.

This review discusses the tertiary phosphines possessing various chiral skeletons that have been used in asymmetric nucleophilic organocatalytic reactions, including annulations of allenes, alkynes, and Morita–Baylis–Hillman (MBH) acetates, carbonates, and ketenes with activated alkenes and imines, allylic substitutions of MBH acetates and carbonates, Michael additions, γ-umpolung additions, and acylations of alcohols.

Tunable Base‐Controlled Regioselective Cascade Reaction of 2‐Mercaptobenzimidazole with Morita–Baylis–Hillman Acetates of Nitroalkenes

AbstractTwo series of heterocyclic compounds, thiazolo[3,2‐a]benzimidazoles and benzimidazo[2,1‐b]‐1,3‐thiazines, were synthesized by the tunable base‐controlled regioselective cascade reaction of 2‐mercaptobenzimidazole with Morita–Baylis–Hillman acetates of nitroalkenes in good yields with high regioselectivities.

One-pot regioselective synthesis of meta-terphenyls via [3 + 3] annulation of nitroallylic acetates with alkylidenemalononitriles.

A highly efficient one-pot method has been developed for the synthesis of meta-terphenyls via a regioselective [3 + 3] annulation-elimination sequence involving Morita-Baylis-Hillman (MBH) acetates of nitroalkenes and alkylidenemalononitriles. The reaction takes place in a regioselective manner under mild conditions (Et3N, room temperature) to afford a wide variety of meta-terphenyls bearing aryl, heteroaryl and styrenyl groups. This novel [3 + 3] annulation takes advantage of the 1,3-bielectrophilic character of MBH acetates and 1,3-binucleophilic character of alkylidenemalononitriles and proceeds in a cascade fashion comprising an SN2' substitution, intramolecular 6-endo-trig Michael addition and double elimination. Representative synthetic transformations of the products, for instance, to meta-terphenyl derived isoindolinones have also been demonstrated.

Novel [4 + 2]-benzannulation to access substituted benzenes and polycyclic aromatic and benzene-fused heteroaromatic compounds.

A common [4 + 2]-benzannulation of Morita-Baylis-Hillman acetates of acetylenic aldehydes with boronic acids has been developed for the synthesis of aromatic and heteroaromatic compounds through tandem allylic substitution/hydroarylative cycloisomerization process. This method provides a facile and general route to substituted benzenes, naphthalenes, other polycyclic aromatics, and various benzene-fused heteroaromatic compounds such as benzofuran, benzothiophene, indole, and carbazoles.

ChemInform Abstract: An Efficient Synthesis of Poly‐Substituted Phenols and Pyridines from Morita—Baylis—Hillman Acetates and Diethyl Oxalacetate.

AbstractVarious phenol derivatives (III) synthesized by a one‐pot reaction of Morita—Baylis—Hillman acetates and sodium diethyl oxalacetate via a [4 + 2]‐cyclization.

Chiral squaramide-catalyzed asymmetric synthesis of pyranones and pyranonaphthoquinones via cascade reactions of 1,3-dicarbonyls with Morita-Baylis-Hillman acetates of nitroalkenes.

Cascade reactions of 1,3-dicarbonyls with Morita-Baylis-Hillman acetates of nitroalkenes using a quinine derived chiral squaramide organocatalyst led to the formation of pyranones and pyranonaphthoquinones in good to excellent yields and high diastereo- and enantioselectivities. Representative examples of the reaction scale-up with a much lower catalyst loading without an appreciable loss of selectivities and synthetic transformations of the products are also reported here. The compounds described herein for the first time were evaluated against the infective bloodstream form of Trypanosoma cruzi, the etiological agent of Chagas disease, since the structures are related to bioactive α-lapachones.