Ethyl Vinyl Ketone Research Articles

Chiral Sterically Congested Phosphane‐Amide Bifunctional Organocatalysts in Asymmetric Aza‐Morita–Baylis–Hillman Reactions of N‐Sulfonated Imines with Methyl and Ethyl Vinyl Ketones

AbstractA series of chiral sterically congested phosphane‐amide bifunctional Lewis bases L1–L3 have been successfully synthesized and their application in asymmetric aza‐Morita–Baylis–Hillman (aza‐MBH) reactions of N‐sulfonated imines with activated olefins such as methyl and ethyl vinyl ketone has been investigated under mild conditions. The corresponding aza‐MBH adducts can be obtained in good‐to‐excellent yields (up to 98 %) and moderate‐to‐good enantioselectivities (up to 91 or 93 % ee) in dichloromethane at room temperature (20 °C) with these novel chiral bifunctional phosphane Lewis bases.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Design, Synthesis, and Stereochemical Evaluation of a Novel Chiral Amine–Palladacycle

AbstractA novel chiral palladacycle containing ortho‐metallated (±)‐1‐(3,6‐dimethylnaphthalen‐2‐yl)‐N,N‐dimethylethylaminewas designed and synthesized by a multi‐step synthesis by using 2,7‐dimethylnaphthalene as the starting material. The structure and palladacycle ring conformation of the triphenylphosphane derivative was investigated by X‐ray structural analysis in the solid state and by 2D ROESY NMR spectroscopy in solution. Through a designed intramolecular steric interaction, the five‐membered naphthylamine chelate can be locked into a fixed conformation, both in the solid state and in solution. The racemic cyclopalladated complex could be efficiently resolved through the formation of its (S)‐prolinato and (S)‐alaninato derivatives. The structure and absolute configuration of the two optically resolved palladium complexes were determined by X‐ray diffraction. Both the (R,R) and (S,S)‐di‐μ‐chlorido dimeric palladium complexes containing the resolved amine ligand was obtained chemoselectively by treating the corresponding prolinato and alaninato derivatives with 1 M hydrochloric acid. Despite the severe interchelate steric constraint within these new organopalladium complexes, the bulky monodentate ligand 3,4‐dimethyl‐1‐phenylphosphole (dmpp) was able to split the chlorido bridges regiospecifically in the position trans to the NMe2 group. With the new palladacycle used as the chiral template, the stereoselectivity of Diels–Alder cycloaddition between dmpp and ethyl vinyl ketone significantly improves relative to that of other analogue complexes.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

ChemInform Abstract: Chiral Bifunctional Organocatalysts in Asymmetric Aza‐Morita—Baylis—Hillman Reactions of Ethyl (Arylimino)acetates with Methyl Vinyl Ketone and Ethyl Vinyl Ketone.

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.

Stereocontrolled Synthesis of Polyfunctionalized cis-Decalins from 2-Methoxyphenols: Total Syntheses of (±)-Eremopetasidione, (±)-3β-Angeloyloxyfuranoeremophilane, and (±)-3β-Methacryloyloxyfuranoeremophilane

A four-step stereocontrolled synthesis of polyfunctionalized cis-decalins is described, involving oxidation of 2-methoxyphenol, intermolecular Diels-Alder reaction, olefination, and Cope rearrangement. Application of this efficient strategy to the total syntheses of (+/-)-eremopetasidione, (+/-)-3 beta-angeloyloxyfuranoeremophilane, and (+/-)-3 beta-methacryloyloxyfuranoeremophilane was accomplished from creosol and ethyl vinyl ketone via a common intermediate 21.

First Evidence of Proline Acting as a Bifunctional Catalyst in the Baylis–Hillman Reaction Between Alkyl Vinyl Ketones and Aryl Aldehydes

AbstractProline in the presence of sodium hydrogen carbonate has been found to be an effective catalyst for the Baylis–Hillman reaction between methyl or ethyl vinyl ketone and aryl aldehydes. Screening of several amine catalysts showed that an ionizable carboxylic function directly linked to the secondary amine catalyst plays an important role in the synthesis of the desired product in good yield. The data obtained has allowed us to suggest, for the first time, that proline, sarcosine, pipecolinic acid and homoproline may act as bifunctional catalysts via a bicyclic enaminolactone species as intermediate. Quantum‐mechanical calculations (PM3/COSMO and ab initio 3‐21G/COSMO) support this mechanism and give more insight into the role of hydrogen carbonate.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Diastereo- and Enantioselective Hydrogenative Aldol Coupling of Vinyl Ketones: Design of Effective Monodentate TADDOL-Like Phosphonite Ligands

We report the first enantioselective reductive aldol couplings of vinyl ketones, which were achieved through the design of a novel monodentate TADDOL-like phosphonite ligand. Specifically, hydrogenation of commercially available methyl vinyl ketone (MVK) or ethyl vinyl ketone (EVK) in the presence of aldehydes 1a-7a using cationic rhodium catalysts modified by chiral TADDOL-like phosphonite ligands AP-I and AP-IV produces aldol adducts 1b-7b and 1c-7c with excellent control of relative and absolute stereochemistry. The absolute stereochemical assignments of the aldol adducts are made in analogy to that determined for the 5-bromophthalimido derivative of aldol adduct 1b and the 2-bromo-5-nitrobenzoate of 3b, which were established by single-crystal X-ray diffraction analysis using the anomalous dispersion method.

ChemInform Abstract: Aza‐Baylis—Hillman Reaction of Salicyl N‐Tosylimines with Methyl Vinyl Ketone, Ethyl Vinyl Ketone or Phenyl Vinyl Ketone.

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.

Dendritic Chiral Phosphine Lewis Bases‐Catalyzed Asymmetric Aza‐Morita–Baylis–Hillman Reaction of N‐Sulfonated Imines with Activated Olefins

AbstractA series of polyether dendritic chiral phosphine Lewis bases was synthesized, and successfully applied to the asymmetric aza‐Morita–Baylis–Hillman reaction of N‐sulfonated imines (N‐arylmethylidene‐4‐methylbenzenesulfonamides) with methyl vinyl ketone (MVK), ethyl vinyl ketone (EVK), and acrolein to give the adducts in good to excellent yields along with up to 97 % ee, which are more effective than our previously reported original chiral phosphine Lewis bases. In addition, the dendrimer‐supported chiral phosphine Lewis bases can be easily recovered and reused.

Polystyrene-supported proline as recyclable catalyst in the Baylis–Hillman reaction of arylaldehydes and methyl or ethyl vinyl ketone

Abstract Polystyrene-supported proline has been used as co-organocatalyst (10 mol%) with imidazole (10 mol%) in the Baylis–Hillman reaction between methyl or ethyl vinyl ketone and arylaldehydes. Recycling studies showed that the proline resin can be used up to five cycles with high isolated yields. This study represents the first example of supported proline as heterogeneous catalyst in the above reaction and broaden the scope of this catalytic material.

Chiral Bifunctional Organocatalysts in Asymmetric Aza-Morita−Baylis−Hillman Reactions of Ethyl (Arylimino)acetates with Methyl Vinyl Ketone and Ethyl Vinyl Ketone

The bifunctional chiral phosphine Lewis base (R)-2'-diphenylphosphino-[1,1'-binaphthalene]-2-ol is an effective organocatalyst in the asymmetric aza-MBH reaction of ethyl (arylimino)acetates 1 with MVK and EVK to give the corresponding adducts in moderate to good yields and good to high enantiomeric excesses under mild conditions.

Chiral Thiourea‐Phosphine Organocatalysts in the Asymmetric Aza‐Morita–Baylis–Hillman Reaction

AbstractA new kind of bifunctional (thio)urea‐phosphine catalyst was synthesized and applied to the aza‐Morita–Baylis–Hillman reaction of N‐sulfonated imines with methyl vinyl ketone, phenyl vinyl ketone, ethyl vinyl ketone or acrolein. Moderate to excellent ee and yields of the products were obtained under mild reaction conditions.

Aza-Baylis–Hillman reaction of salicyl N-tosylimines with methyl vinyl ketone, ethyl vinyl ketone or phenyl vinyl ketone

Reactions of salicyl N-tosylimines with methyl vinyl ketone, ethyl vinyl ketone or phenyl vinyl ketone proceeded smoothly under mild conditions to give the corresponding chromanes or aza-Baylis–Hillman adducts in moderate to excellent yields in the presence of phosphine or nitrogen Lewis base.

Rhodium-Catalyzed Reductive Mannich Coupling of Vinyl Ketones to N-Sulfonylimines Mediated by Hydrogen

Catalytic hydrogenation of methyl vinyl ketone (MVK) and ethyl vinyl ketone (EVK) in the presence of N-(o-nitrophenylsulfonyl)imines 8a-13a at ambient pressure with tri-2-furylphosphine-ligated rhodium catalysts enables formation of Mannich products 8b-13b and 8c-13c with moderate to good levels of syn-diastereoselectivity. As revealed by an assay of various N-protecting groups, excellent yields of reductive Mannich product also are obtained for N-arylimines 1a-4a, although diminished levels of syn-diastereoselectivity are observed. Coupling of MVK to imine 8a under a deuterium atmosphere provides deuterio-8b, which incorporates a single deuterium atom at the former enone beta-position.

A selective [4 + 2]-like cycloaddition of α, β-unsaturated ketone on Si(1 1 1)-7 × 7

The interaction of ethyl vinyl ketone (EVK) with Si(1 1 1)-7 × 7 has been investigated using high-resolution electron energy loss spectroscopy (HREELS), X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations. The disappearance of both stretching vibrations of CH 2 (3099 cm −1) and C O (1684 cm −1) coupled with the appearance of new C C stretching mode (1660 cm −1) in the HREELS spectra of chemisorbed EVK clearly demonstrates the direct involvement of conjugated C C and C O bonds to form a SiC 1H 2C 2H C 3(C 4H 2C 5H 3)OSi surface species via [4 + 2]-like cycloaddition in a highly selective manner. In addition, XPS studies show that the C1s binding energies of C 1/C 2 and C 3 upon chemisorption display chemical downshifts of 0.8 eV and 2.2 eV, respectively, further confirming the proposed [4 + 2]-like cycloaddition reaction for the EVK/Si(1 1 1)-7 × 7 system. DFT theoretical calculations suggest that the proposed [4 + 2]-like cycloadduct is thermodynamically most favorable.

Ruthenium–Lewis Acid Catalyzed Asymmetric Diels–Alder Reactions between Dienes and α,β‐Unsaturated Ketones

The complex [Ru(Cp)(R,R-BIPHOP-F)(acetone)][SbF(6)], (R,R)-1 a, was used as catalyst for asymmetric Diels-Alder reactions between dienes (cyclopentadiene, methylcyclopentadiene, isoprene, 2,3-dimethylbutadiene) and alpha,beta-unsaturated ketones (methyl vinyl ketone (MVK), ethyl vinyl ketone, divinyl ketone, alpha-bromovinyl methyl ketone and alpha-chlorovinyl methyl ketone). The cycloaddition products were obtained in yields of 50-90 % and with enantioselectivities up to 96 % ee. Ethyl vinyl ketone, divinyl ketone and the halogenated vinyl ketones worked best and their reactions with acyclic dienes consistently provided products with >90 % ee. alpha-Chlorovinyl methyl ketone performed better than alpha-bromovinyl methyl ketone. The reaction also provided a [4.3.1]bicyclic ring system in 95 % ee through an intramolecular cycloaddition reaction. Crystal structure determinations of [Ru(Cp)((S,S)-BIPHOP-F)(mvk)][SbF(6)], (S,S)-1 b, and [Ru(Cp)((R,R)-Me(4)BIPHOP-F)(acrolein)][SbF(6)], (R,R)-2 b, provided the basis for a rationalization of the asymmetric induction.

Degradation kinetics of acrylonitrile/methyl vinyl ketone copolymers

AbstractMethyl vinyl ketone (MVK) was first used to successfully copolymerize with acrylonitrile (AN). This was achieved by using azobisisobutyronitrile as the initiator. Differential scanning calorimetry results of the degradation of AN/MVK copolymers in air are presented. The apparent activation energy of degradation of the copolymers was calculated with Kissinger method. Effects of copolymerization conditions on the apparent activation energy of the copolymers were studied. It has been found that increasing dimethyl sulfoxide concentration in the solvent mixture leads to a rapid increase in the degradation apparent activation energy of AN/MVK copolymers. The apparent activation energy decreases quickly along with increase in the comononer MVK concentration, and this change becomes less prominent as the weight ratio of MVK/AN goes beyond 7/93. The apparent activation energy shows a trend of increase as the copolymerization temperature increases. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1386–1390, 2007

Aza‐Morita—Baylis—Hillman Reaction of Ethyl (Arylimino)acetate with Methyl Vinyl Ketone and Ethyl Vinyl Ketone.

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 Induction in Hydrogen-Mediated Reductive Aldol Additions to α-Amino Aldehydes Catalyzed by Rhodium: Selective Formation of syn-Stereotriads Directed by Intramolecular Hydrogen-Bonding

Rhodium-catalyzed hydrogenation of methyl vinyl ketone and ethyl vinyl ketone in the presence of N-Boc-alpha-aminoaldehydes 3a-8a at ambient temperature and pressure results in reductive C-C coupling to furnish aldol adducts 3b-8b and 3c-8c, respectively, which incorporate stereotriads that embody high levels of syn-aldol selectivity accompanied by high levels of anti-Felkin-Anh control. The collective data are consistent with a catalytic mechanism involving addition of the Z(O)-rhodium enolate to the sterically less-encumbered aldehyde pi-face of an intramolecularly hydrogen-bonded chelate through a Zimmerman-Traxler type transition structure. Stereochemical assignments are supported by single-crystal X-ray diffraction analysis of 5b-O-3,5-dinitrobenzoate, iso-5b, N-Me-iso-5b-O-3,5-dinitrobenzoate, and 7b. As revealed by HPLC analysis, optical purity of the stereochemically labile alpha-aminoaldehydes is completely preserved under the conditions of hydrogen-mediated aldol coupling. Deletion of the intramolecular hydrogen bond, as in the case of N-methyl-N-Boc-l-leucinal N-Me-5a, inverts stereoselectivity to furnish the Felkin-Anh product N-Me-iso-5b in 17% yield. Additionally, reactions performed in the presence of tert-amyl alcohol (10 equiv) exhibit markedly lower levels of anti-Felkin-Anh control (7:1 versus > or = 20:1). The collective studies suggest that intramolecular hydrogen bonding plays a key role in both activating the alpha-aminoaldehyde toward addition and directing facial selectivity.

Aza-Morita–Baylis–Hillman reaction of ethyl (arylimino)acetate with methyl vinyl ketone and ethyl vinyl ketone

Aza-Morita–Baylis–Hillman (aza-MBH) reaction of ethyl (arylimino)acetate with methyl vinyl ketone and ethyl vinyl ketone has been investigated. We found that aza-MBH adducts 1 could be formed in the presence of DABCO (30 mol %) and the corresponding adducts 2 could be obtained in the presence of PPh 3 (30 mol %) in moderate to good yields in acetonitrile under mild conditions, respectively.

Monomer apparent reactivity ratios for acrylonitrile/methyl vinyl ketone copolymerization system

AbstractMethyl vinyl ketone was firstly used to successfully copolymerize with acrylonitrile. This was achieved by using azobisisobutyronitrile as the initiator, and dimethyl sulfoxide as the solvent. Effect of copolymerization systems on monomer apparent reactivity ratios for copolymer of acrylonitrile with methyl vinyl ketone was studied for contrast. Values of monomer apparent reactivity ratios were calculated by Kelen–Tudos method. It has been found that the apparent reactivity ratios in aqueous suspension polymerization system were similar to those in solution polymerization system at polymerization conversion less than 20%. Beyond 50% of conversion, the changes of monomer apparent reactivity ratios become less prominent. In water‐rich reaction medium [(H2O/dimethylsulfoxide (DMSO)>80/20), monomer apparent reactivity ratios were approximately equivalent to those in aqueous suspension polymerization system. In DMSO‐rich reaction medium (DMSO/H2O > 80/20), apparent reactivity ratios were similar to those in solution polymerization system. Values of apparent reaction ratios both decreased when AN/MVK copolymer was synthesized in DMF and DMAc. The values of apparent reaction ratios gradually tend to 1 with increasing the copolymerization temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4045–4048, 2006