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We describe herein a facile method to access 2,3-epoxyesters with fluorine-containing substituents at their 3-position starting from the corresponding enoates by utilization of the low-costed and easy-to-handle reagent, NaOCl·5H2O. Because very little has been disclosed about the reactivity of such 2,3-epoxyesters, their epoxy ring opening by a variety of nucleophiles was carried out and we succeeded in clarifying these chemo- as well as regioselective processes proceeding via the SN2 mechanism to mainly afford 2-substituted 3-hydroxyesters usually in a highly anti selective manner.

A novel strategy has been developed for the synthesis of 2,3‐diarylindanones and 2‐arylindenes through the formation of trisubstituted α,β‐unsaturated esters by the ring opening of 2,3‐diarylcyclopropenones in the presence of a catalytic amount of TPP under mild reaction conditions. Initially, PPh3 activates the diarycyclopropenone to generate the phosphonium adduct, which simultaneously reacts with 4‐hydroxycoumarins to afford α,β‐unsaturated esters instead of Wittig olefination. Subsequently, these α,β‐unsaturated esters undergo a smooth Friedel–Crafts‐type cyclization with arenes in the presence of AlCl3 to give a new series of 2,3‐diarylindanones in good to excellent yields. Additionally, the reduction of α,β‐unsaturated esters with NaBH4 followed by acid‐catalyzed cyclization of the resulting allylic alcohols afforded 2‐arylindenes in good yields. This is the first report on the use of α,β‐unsaturated esters as precursors for the synthesis of diarylindanones and arylindenes. [ABSTRACT FROM AUTHOR]

The Ru-catalyzed highly selective alkoxycarbonylation of allenes with aliphatic alcohols (also as solvent) allow to produce useful α,β-unsaturated esters in good to excellent yields at 70 °C. Efficient regioselectivity could be controlled in the presence of N-ligands while the P-ligands had no influence on the conversion of substrates and the chemo/regioselectivity of target products. By involving N-ligand 4,7-dimethyl-1,10-phenanthroline in the catalytic system, α,β-unsaturated esters were obtained with high conversion and chemo/regioselectivity (conversion up to 99%, chemical selectivity up to 99%, regioselectivity of branched ester/linear ester up to 89/11). [ABSTRACT FROM AUTHOR]

Non‐stabilized aryldiazoalkanes were utilized for highly enantioselective catalytic 1,3‐dipolar cycloaddition reaction in the presence of chiral oxazaborolidinium ion (COBI) as a Lewis acid catalyst. Enantioenriched 2‐pyrazolines were obtained in excellent yields (up to >99%) with excellent enantioselectivities (up to >99%). [ABSTRACT FROM AUTHOR]

2013, 355: 1403 33 Chew, R J. Teo, K Y. Huang, Y. Li, B.-B. Li, Y. Pullarkat, S A. Leung, P.-H. Chem. Commun. Keywords: copper(I) catalysis; asymmetric catalysis; conjugate addition; hydrophosphination; , -unsaturated esters EN copper(I) catalysis asymmetric catalysis conjugate addition hydrophosphination , -unsaturated esters 2228 2240 13 07/03/23 20230718 NES 230718 Metal-catalyzed asymmetric hydrophosphination with secondary phosphines has been developed as one of the most important methods to construct chiral phosphines, which serve as powerful ligands and excellent organocatalysts. J. Am. Chem. Soc. 2010, 132: 5562 16 Huang, Y. Pullarkat, S A. Li, Y. Leung, P.-H. Chem. Commun. 2000, 19: 950 10 Sadow, A D. Haller, I. Fadini, L. Togni, A. J. Am. Chem. Soc. 2004, 126: 14704 11 Chew, R J. Leung, P.-H. Chem. Rec. 2016, 16: 141 12 Li, Z. Duan, W.-L. [Extracted from the article]

We describe herein a facile method to access 2,3-epoxyesters with fluorine-containing substituents at their 3-position starting from the corresponding enoates by utilization of the low-costed and easy-to-handle reagent, NaOCl·5H 2 O. Because very little has been disclosed about the reactivity of such 2,3-epoxyesters, their epoxy ring opening by a variety of nucleophiles was carried out and we succeeded in clarifying these chemo- as well as regioselective processes proceeding via the S N 2 mechanism to mainly afford 2-substituted 3-hydroxyesters usually in a highly anti selective manner., (Copyright © 2024, Miyashita et al.)

A cobalt‐catalyzed asymmetric reduction of β,β‐dialkyl α,β‐unsaturated esters with polymethylhydrosiloxane (PMHS) was reported to deliver the corresponding esters containing a chiral trialkyl carbon center at β‐position with up to 97 % yield and 98 % ee. The chiral tridentate ligand oxazoline iminopyridine (OIP) could perform well for the asymmetric reduction instead of chiral bidentate ligands. This operationally simple protocol shows a broad scope of substrates using one equivalent of readily available PMHS as a cheap and easy‐to‐handle reductive reagent. [ABSTRACT FROM AUTHOR]

A manipulative simple and efficient green methodology for the synthesis of β-sulfonyl esters from sulfonyl hydrazides and acrylic esters promoted by DABCO (1,4-diazabicyclo[2.2.2]octane) is described. The reaction is conducted through sulfa-Michael addition reaction in the absence of solvent at 75°C within 2–3 h. The effects of different bases, molar ratio of DABCO, temperature and time parameters on yield of reaction were investigated. [ABSTRACT FROM AUTHOR]

A convenient method for reductive Horner–Wadsworth–Emmons (HWE) olefination is described. The E‐selective HWE homologation of various esters to α,β‐unsaturated esters was readily achieved and gave the desired products in good‐to‐moderate yields under mild conditions. The one‐pot reaction proceeds through an in situ generated aldehyde, formed via the partial reduction of an ester with lithium diisobutyl‐t‐butoxyaluminum hydride. The formation of cyclized metal acetal and subsequent decompose to the aldehyde for the olefination was found to be a crucial step in this C2‐carbon homologation protocol. [ABSTRACT FROM AUTHOR]

[Display omitted] • Reusable Co/N-doped carbon catalyst. • Cheap and abundant feedstocks. • Reductive coupling. • High step and atom efficiency. • Chemoselective generation of β -amino acid esters. Reductive coupling of two unsaturated substances for the construction of functional molecules remains a significant challenge due to the difficulty in controlling the chemoselective reduction. Here, by developing a cobalt and nitrogen co-doped hierarchically porous carbon material (Co/N-HPNC) deriving from the homomorphic Zr-based metal-organic framework (MOF), we describe, for the first time, its application as a bifunctional catalyst for direct access to β -amino acid esters via chemoselective reductive hydroamination of the α, β -unsaturated esters with cheap and air-stable nitroarenes. The catalyst structure-performance relationship reveals that the N-dopants benefit the adsorption of the nitroarenes and protons, and the active cobalt species run the transfer hydrogenation of the nitroarenes, such a synergetic effect results in chemoselective formation of the desired products. The developed catalytic transformation proceeds with good substrate and functionality tolerance, the use of easily accessible and reusable base metal catalyst, operational simplicity, high step and atom efficiency, and easy applicability for further fabrication of functional molecules, which offers a sustainable platform for direct synthesis of valuable products from bulk raw materials. [ABSTRACT FROM AUTHOR]

In this paper, C–N bond formation between 2,3-dihydrophthalazine-1(4H),4-dione (phthalhydrazide) and α,β-unsaturated esters was investigated and a new series of phthalazine derivatives was synthesized using an efficient and simple method under solvent-free conditions. An aza-Michael addition of phthalhydrazide to both acrylic and fumaric esters led to N-mono-substituted phthalhydrazides (as mono-Michael adduct) in the presence of tetrabutylammonium bromide as a high polar media, and 1,4-diaza-bicyclo[2,2,2]octane as an available organic base. In this reaction, the N1,N2-bis-Michael adduct was not observed at all. Also, reactions were performed at 90°C and yields of products were good to excellent.

In this paper, we describe a new, simple and efficient strategy for the formation of novel and valuable acyl hydrazide derivatives from reaction between diverse acyl hydrazides and α,β-unsaturated esters in the presence of 1,4-diaza-bicyclo[2,2,2]octane (DABCO) – an inexpensive base – and tetrabutylammonium bromide (TBAB) – an ionic organic salt – under solvent-free conditions. In the reaction, double Michael adducts were produced in good yields in 7 h when acrylic esters were used as Michael acceptors. Surprisingly, no double Michael adducts were produced with fumaric esters, and single Michael adducts were the only products of these reactions in 10 h.

A new series of spiro[[1,3]dithiolane-2,3′-indolines]-2′-one derivatives was synthesized using Michael addition reaction of spiro[[1,3]dithiolane-2,3′-indolin]-2′-one to various α,β-unsaturated esters as well as direct alkylation of this compound with alkyl dihalides. Michael reaction of spiro[[1,3]dithiolane-2,3′-indolin]-2′-one and α,β-unsaturated esters produced related Michael adduct in the presence of tetrabutylammonium bromide and base 1,4-diazabicyclo[2.2.2]octane in good to excellent yields at 80°C under solvent-free conditions. Also, direct alkylation of spiro[[1,3]dithiolane-2,3′-indolin]-2′-one by dihaloalkanes in the presence of base K2CO3 afforded the corresponding products in good yields under the same conditions.

α,β-Unsaturated esters are versatile building blocks for organic synthesis and of significant importance for industrial applications. A great variety of synthetic methods have been developed, and quite a number of them use aldehydes as precursors. Herein we report a chemo-enzymatic chain elongation approach to access α,β-unsaturated esters by combining an enzymatic carboxylic acid reduction and Wittig reaction. Recently, we have found that Mycobacterium sp. was able to reduce phenylacetic acid (1a) to 2-phenyl-1-ethanol (1c) and two sequences in the Mycobacterium sp. genome had high identity with the carboxylic acid reductase (CAR) gene from Nocardia iowensis. These two putative CAR genes were cloned, overexpressed in E. coli and one of two proteins could reduce 1a. The recombinant CAR was purified and characterized. The enzyme exhibited high activity toward a variety of aromatic and aliphatic carboxylic acids, including ibuprofen. The Mycobacterium CAR catalyzed carboxylic acid reduction to give aldehydes, followed by a Wittig reaction to afford the products α,β-unsaturated esters with extension of two carbon atoms, demonstrating a new chemo-enzymatic method for the synthesis of these important compounds.

[Display omitted] The phospha-Michael addition (PMA) to many Michael acceptors like nitro-olefins, cyclic enones is well known. Chalcones and α,β-unsaturated esters are rarely employed in PMA reaction. In this article, we report the PMA of biphenylphosphine oxide to chalcone and α , β -unsaturated esters using the newly identified organocatalyst 1,1-diaminobenzalazine. The reaction has wide substrate scope, and the products were formed with very good yields. This work establishes the versatility of the organocatalyst 1,1-diaminobenzalazine in producing substituted 3-(diphenylphosphoryl)-1,3-diphenylpropan-1-ones. [ABSTRACT FROM AUTHOR]

In this paper, C–N bond formation between 2,3-dihydrophthalazine-1(4H),4-dione (phthalhydrazide) andα,β-unsaturated esters was investigated and a new series of phthalazine derivatives was synthesized using an efficient and simple method under solvent-free conditions. An aza-Michael addition of phthalhydrazide to both acrylic and fumaric esters led to N-mono-substituted phthalhydrazides (as mono-Michael adduct) in the presence of tetrabutylammonium bromide as a high polar media, and 1,4-diaza-bicyclo[2,2,2]octane as an available organic base. In this reaction, the N1,N2-bis-Michael adduct was not observed at all. Also, reactions were performed at 90°C and yields of products were good to excellent. [ABSTRACT FROM PUBLISHER]

In this paper, we describe a new, simple and efficient strategy for the formation of novel and valuable acyl hydrazide derivatives from reaction between diverse acyl hydrazides andα,β-unsaturated esters in the presence of 1,4-diaza-bicyclo[2,2,2]octane (DABCO) – an inexpensive base – and tetrabutylammonium bromide (TBAB) – an ionic organic salt – under solvent-free conditions. In the reaction, double Michael adducts were produced in good yields in 7 h when acrylic esters were used as Michael acceptors. Surprisingly, no double Michael adducts were produced with fumaric esters, and single Michael adducts were the only products of these reactions in 10 h. [ABSTRACT FROM PUBLISHER]

A new series of spiro[[1,3]dithiolane-2,3′-indolines]-2′-one derivatives was synthesized using Michael addition reaction of spiro[[1,3]dithiolane-2,3′-indolin]-2′-one to various α,β-unsaturated esters as well as direct alkylation of this compound with alkyl dihalides. Michael reaction of spiro[[1,3]dithiolane-2,3′-indolin]-2′-one and α,β-unsaturated esters produced related Michael adduct in the presence of tetrabutylammonium bromide and base 1,4-diazabicyclo[2.2.2]octane in good to excellent yields at 80°C under solvent-free conditions. Also, direct alkylation of spiro[[1,3]dithiolane-2,3′-indolin]-2′-one by dihaloalkanes in the presence of base K2CO3afforded the corresponding products in good yields under the same conditions. [ABSTRACT FROM PUBLISHER]

Herein, we disclose the N-heterocyclic carbene (NHC)-catalyzed [3+3] annulation of challenging esters with methyl ketoimines for the highly enantioselective synthesis of intriguing δ-lactams featuring various substituent patterns. The annulation occurs under mild conditions and offers good tolerance, good yields and excellent enantioselectivities. The six-membered heterocyclic products are valuable for the synthesis of bioactive molecules. [ABSTRACT FROM AUTHOR]

A new process has been developed for the iridium(I)-catalyzed vinylic C−H borylation of α,β-unsaturated esters with bis(pinacolato)diboron (B2pin2). These reactions proceeded in octane at temperatures in the range of 80-120 °C to afford the corresponding alkenylboronic compounds in high yields with excellent regio- and stereoselectivities. The presence of an aryl ester led to significant improvements in the yields of the acyclic alkenylboronates. Crossover experiments involving deuterated substrates as well as a mixture of stereoisomers confirmed that this reaction proceeds via a 1,4-addition/β-hydride elimination mechanism. Notably, this reaction was also used to develop a one-pot borylation/Suzuki-Miyaura cross-coupling procedure. [ABSTRACT FROM AUTHOR]

Condensation of Hörner–Wadsworth–Emmons reagents 3 and ketones 2 with a perfluoroalkyl (Rf) moiety prepared in situ was proved to be significantly efficient and powerful methods for the construction of a wide variety of α,β-unsaturated esters with Rf and R 1 groups both at the β-position due to convenient avoidance of usually tedious as well as troublesome isolation steps of these ketones 2 . [ABSTRACT FROM AUTHOR]

Amine-containing carbon catalysts were synthesized to study the production of α,β-unsaturated esters by Knoevenagel condensation of buthyraldehyde and ethyl cyanoacetate. The solids were characterized by XRD, XPS, FTIR, elemental analyses, CO 2 adsorption measurements and N 2 adsorption-desorption isotherms. Monoethanolamine-functionalization on the carbon led to structural changes while keeping relatively high surface areas. Although a great number of basic sites provided a good performance in the reaction, leaching of these sites at elevated temperatures accounted for deactivation of the catalyst. The best performance towards ethyl 2-cyano-3-propylacrylate ester was obtained for ACN10 (conversion = 10.7%; selectivity = 100%) at 348 K, being reused for five times. [ABSTRACT FROM AUTHOR]

Hexachlorobutadiene reacts with MeONa in refluxing methanol to give ( Z)-4,4-dimethoxy2-oxobut-3-enoic acid and 2,4,4-trichloro-1,1,1,3-tetramethoxybut-2-ene, which were converted to methyl ( Z)-4,4-dimethoxy-2-oxobut-3-enoate and methyl ( Z)-2,4,4-trichloro-3methoxybut-2-enoate upon treatment with CHN and acid hydrolysis, respectively. [ABSTRACT FROM AUTHOR]

Rate coefficients for reactions of a series of α,β-unsaturated esters with OH and NO3 radicals, O3 and Cl atoms have been estimated using different methods: i.e., physico-chemical correlations and Structure Activity Relationships (SARs). In this study new correlations to estimate rate coefficients have been proposed (only for α,β-unsaturated esters): = (13.9 ± 2.8) + (2.75 ± 0.26) × log (kOH); log (kOH) = (4.93 ± 1.14) + (1.60 ± 0.12) × log (kCl); ln(kOH/cm3 molecule−1 s−1) = (1.71 ± 0.21) × EHOMO/eV − (6.25 ± 2.24); ln( /cm3 molecule−1 s−1) =(5.94 ± 0.35) × EHOMO/eV + (27.87 ± 3.65); ln( /cm3 molecule−1 s−1) = (2.20 ± 0.63) × EHOMO/eV − (16.75 ± 6.65) and ln(kCl/cm3 molecule−1 s−1) = (0.21 ± 0.23) × (EHOMO)/eV − (19.8 ± 2.4). The group reactivity factors necessary to estimate the rate coefficients by SAR methods have also been calculated for a series of α,β-unsaturated esters for the first time: f(–C(O)O(CH2)3CH3), f(–C(O)O(CH2)5CH3), f(–C(O)OCH2CH(CH2CH3)CH2CH2CH2CH3) for reactions with the NO3 radical, OH radical and O3. Furthermore, f(–C(O)OCH3), f(–C(O)OCH2CH3), f(–C(O)O(CH2)3CH3), f(–C(O)OCH2CH2CH2CH2CH2CH3), f(–C(O)OCH2CH(CH2CH3)CH2CH2CH2CH3) for reactions with chlorine atoms have been estimated. The results show that for NO3 and OH radicals these methods are generally satisfactory. In the case of Cl atoms, all methods used in this study reproduce the rate coefficient within a factor of 1.5. In general the best method for estimating the rate coefficient of α,β-unsaturated esters with the main atmospheric oxidants is the correlation of ln k versus EHOMO. [ABSTRACT FROM AUTHOR]

Highlights: [•] Development of a useful one-pot preparation method of allylic alcohols with fluorinated alkyl groups at the γ position. [•] Wide application to substrates with a variety of fluorine-containing alkyl groups. [•] No requirement of isolation of the reactive and tough-to-handle intermediary aldehydes. [ABSTRACT FROM AUTHOR]

α,β-Unsaturated esters have been employed as substrates in iridium-catalyzed asymmetric hydrogenation. Full conversions and good to excellent enantioselectivities (up to 99 % ee) were obtained for a broad range of substrates with both aromatic- and aliphatic substituents on the prochiral carbon. The hydrogenated products are highly useful as building blocks in the synthesis of a variety of natural products and pharmaceuticals. [ABSTRACT FROM AUTHOR]

Abstract: A nucleophilic carbene catalyzed redox esterification between α-halo-α,β-unsaturated aldehydes and various alcohols has been developed. Interestingly, the reaction provided α,β-unsaturated esters instead of the saturated α-halo substituted esters as the only product in good to high yield with excellent trans-selectivity, presumably via the umpolung-halo-elimination pathway. [Copyright &y& Elsevier]

Abstract: A highly practical method to access β-sulfido carbonyl compounds was developed, which could be conducted without any expensive reagent, special apparatus/technique, and no requirement of metal catalysts. β-Sulfido carbonyl compounds were formed at room temperature, in short time and with high chemoselectivity in good to excellent yields. A plausible mechanism for the role of Rongalite®, as a promoter for the cleavage of disulfides generating thiolate anions that then undergo facile thia-Michael addition to α,β-unsaturated ketones and esters is proposed. [Copyright &y& Elsevier]

Abstract: A direct diastereoselective titanium-mediated intermolecular coupling of internal alkynes with dialkyl carbonates under Kulinkovich-type reaction conditions is presented. The influence of the structures of the coupling partners on the yields and regioselectivities of this transformation is described. [Copyright &y& Elsevier]

• A cycloaddition reaction of β-diazo-α,α-difluoromethylphosphonates with α,β-unsaturated esters was reported. • The reaction features mild conditions and wide substrate scope, also can be conducted in large-scale. • This reaction provides an easy access to difluoromethylene phosphonate-containing pyrazoline carboxylates. (β-diazo-α,α-difluoroethyl)phosphonates as an analog of difluoro diazoethane has been designed as a powerful tool for the assembly of α,α-difluorinated phosphonate-containing molecules. Here, we report a [3+2] dipolar cycloaddition reaction of in situ generated (β-diazo-α,α-difluoroethyl)phosphonates and α,β-unsaturated esters. This mild protocol delivers a diverse array of (β-amino-α,α-difluoroethyl)phosphonates and simple unsaturated esters into highly valuable difluoromethylene phosphonate-containing pyrazoline carboxylates with good chemical yields. Furthermore, the utility of this method has been demonstrated by the large-scale synthesis. An efficient cycloaddition reaction of (β-diazo-α,α-difluoroethyl)phosphonates and α,β-unsaturated esters has been developed, which affords highly valuable difluoromethylene phosphonate-containing pyrazoline carboxylates with good chemical yields [Display omitted]. [ABSTRACT FROM AUTHOR]

Abstract: The title compounds have been synthesized by irradiation of acetonitrile solutions of perfluoroacid esters and diesters containing tetrabutylammonium iodide. They are versatile synthetic intermediates from which ketenes, Reformatsky adducts, α,β-unsaturated esters and α-hydroesters can be prepared. [Copyright &y& Elsevier]

Abstract: (E)-α,β-Unsaturated ketones 1 or esters 2 can be obtained with complete stereoselectivity by reaction of different 2-chloro-3-hydroxy ketones 3 or esters 4 and CrCl2. A comparative study of the results of synthesis of ketones 1 with CrCl2 or samarium is performed. A mechanism to explain both β-elimination reactions has been proposed. [Copyright &y& Elsevier]

Abstract: We describe a highly efficient new methodology for the synthesis of (E)-α,β-unsaturated esters from aldehydes. In our DMAP-catalyzed reaction, both aromatic as well as aliphatic aldehydes furnish the desired products highly regio- and stereoselectively if treated with commercially available or synthetically easily accessible malonic acid half ester. A large scale application in the synthesis of p-methoxycinnamates, which are of use as sunscreen ingredients, is described. [Copyright &y& Elsevier]

Abstract: The radical-mediated hydroxyalkylation of α,β-unsaturated esters with alkyl iodides, trialkylborane, water and KF in THF gave the corresponding α-hydroxy esters. The synthetic advantage of the method was demonstrated by a short-step total synthesis of (±)-tanikolide. [Copyright &y& Elsevier]

Thermal Arndt–Eistert reactions of N ‐tosyl cyclic α‐amino acids were studied to explore the preparation of α,β‐unsaturated esters bearing a terminal tosylamino group. For L‐ N ‐tosyl‐aziridine 2‐carboxylic acid and L‐ N ‐tosyl‐azetidine 2‐carboxylic acid, the corresponding ( E )‐α,β‐unsaturated esters were obtained stereospecifically. [ABSTRACT FROM AUTHOR]

Abstract: The proteolytic processing of polyproteins by the 3CL protease of severe acute respiratory syndrome coronavirus is essential for the viral propagation. A series of tripeptide α,β-unsaturated esters and ketomethylene isosteres, including AG7088, are synthesized and assayed to target the 3CL protease. Though AG7088 is inactive (IC50 >100μM), the ketomethylene isosteres and tripeptide α,β-unsaturated esters containing both P1 and P2 phenylalanine residues show modest inhibitory activity (IC50 =11–39μM). The Phe-Phe dipeptide inhibitors 18a–e are designed on the basis of computer modeling of the enzyme–inhibitor complex. The most potent inhibitor 18c with an inhibition constant of 0.52μM is obtained by condensation of the Phe-Phe dipeptide α,β-unsaturated ester with 4-(dimethylamino)cinnamic acid. The cell-based assays also indicate that 18c is a nontoxic anti-SARS agent with an EC50 value of 0.18μM. [Copyright &y& Elsevier]

An efficient procedure for the synthesis of some carboacyclic nucleosides via microwave-assisted Michael addition of various nucleobases to α,β-unsaturated esters in the presence of tetrabutylammonium bromide (TBAB) and DABCO is described. Using this method, some pyrimidine and purine nucleobases have been alkylated regioselectively in moderate to high yields and short reaction time. [ABSTRACT FROM AUTHOR]

Abstract: Functionalized Z-vinylic tellurides were used in substitution reactions with lower order cyanocuprates leading to α,β-unsaturated ketones and esters in good yields. In the case of acyclic tellurides, the product was obtained in high diastereoselectivity. The control of the stereoselectivity was achieved by simple change of the reaction temperature. [Copyright &y& Elsevier]

The Horner-Wadsworth-Emmons reaction of both (Still''s reagent) and (Ando''s reagent) with aldehydes was studied. Tris[2-(2-methoxyethoxy)ethyl]amine (TDA-1) was shown to be an efficient additive when the reaction was performed in THF at -78 °C. Selectivities close to 95% were obtained in the condensation of with aromatic aldehydes. The use of a 5-fold excess of 18C6 in this reaction had already been reported. However, we have defined conditions in which only catalytic amounts are required. [Copyright &y& Elsevier]

Stereoselective synthesis of α,β-unsaturated esters 7 and 8 was achieved through Horner–Wadsworth–Emmons reaction of β,β-disubstituted α,β-unsaturated aldehydes. Thus, aldehydes 6 undergo olefination with phosphonate carbanion generated from triethyl phosphonoacetate 3 and lithium hydroxide or butyl lithium/DMPU to give (E)-α,β-unsaturated esters 7 with excellent selectivity. The treatment of 6 with the new Horner–Emmons reagents, ethyl(diphenylphosphono)acetate 4a and ethyl (di-o-tolyl-phosphono) acetate 4b in the presence of benzyltrimethyl ammonium hydroxide (Triton B) afforded (Z)-α,β-unsaturated esters 8 with 73–89% selectivity. The esters 7 and 8 were converted to (2E)- and (2Z)-4-cycloalkylidenebut-2-enoic acids 9 and 10, respectively. [ABSTRACT FROM AUTHOR]

The catalytic activity and selectivity of heterodonor phosphine rhodium catalysts prepared in situ were tested in the hydroformylation of functional alkenes (ethyl acrylate, methyl methacrylate, styrene, 4-vinyl-1-cyclohexene, dicyclopentadiene and cis-1,2,3,6-tetrahydrophthalic anhydride). Systematic variation of the heterodonor atom in the ortho position of the ligand showed that the heterodonor atom has a significant influence on the activities and selectivities of the reaction. However, the activity seems to depend mainly on the modifying ligand, and the regioselectivity mainly on the substrate (i.e., the structure and functionality of the alkene). Nevertheless, regioselective control is only obtained through synergy between the substrate and the catalyst. Clear regiocontrol was observed in the hydroformylation of α,β-unsaturated esters and styrene with an in situ formed o-(thiomethylphenyl)diphenylphosphine rhodium catalyst. [ABSTRACT FROM AUTHOR]

A practical and high yielding synthesis of α,β-unsaturated esters from aldehydes and 1,1-diethoxyethylene was developed.

Abstract: A facile one-step method for the elimination of the dimethylamino group in Eschenmoser’s methylenation has been developed using a combination of 2-chloro-4,6-dimethoxy-1,3,5-triazine and triethylamine. The chemoselective elimination of the dimethylamino group occurred in compounds possessing either a diethylamino group or an alkylsulfanyl group. [Copyright &y& Elsevier]

Synthesis of (E)-α,β-unsaturated esters in high yields and with total stereoselectivity is achieved from α-halo-β-hydroxy esters promoted by catalytic amounts of SmI2. The starting compounds were easily prepared from α-halo esters and aldehydes as a mixture of stereoisomers. A mechanism is proposed to explain this samarium(II)-promoted catalytic β-elimination reaction. [ABSTRACT FROM AUTHOR]

Abstract: The chemoselective SN2′ reaction of a variety of primary nitroalkanes to dialkyl 2-(bromomethyl)fumarates can be efficiently performed under cetyltrimethylammonium hydroxide (CTAOH) catalysis. The α,β-unsaturated esters were obtained in satisfactory to good yields with the complete retention of the nitro group. [Copyright &y& Elsevier]

The first atomically precise palladium nanocluster catalyzed one-pot tandem oxidation-wittig reactions was reported. • The Pd 3 Cl /MSNs was synthesized and well characterized. • The tandem oxidation process of alcohol and phosphorous ylide was realized. • The Pd 3 Cl /MSNs could be easily separated and shows excellent reusability. • This represents the first example of tandem reaction catalyzed by Pd nanocluster. The mesoporous silica nanosphere supported palladium nanocluster was synthesized through a simple impregnation method and well characterized. The as prepared catalyst shows excellent catalytic performance in tandem oxidation process (TOP) of alcohol and phosphorous ylide, which provides an efficient access to α,β-unsaturated esters with high yields utilizes 1 atmosphere of molecular oxygen as sole oxidant. This work represents the first example of atomically precise palladium nanocluster catalyzed tandem oxidation process of alcohol and phosphorous ylide and is expected to open new horizons for nanoclusters in the tandem reactions. [ABSTRACT FROM AUTHOR]