Advances in the Synthesis of α-Methylenelactones

Petragnani, Nicola; Ferraz, Helena M. C.; Silva, Gil V. J.

doi:10.1055/s-1986-31615

Cited by 148 publications

(25 citation statements)

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“…5-Hydroxyhexanoate 16a was completely converted into the lactone 17a by treatment of the obtained mixture with CF 3 CO 2 H in DCM. 31 P NMR data of the lactone 17a revealed the formation of two diastereoisomers in a ratio 0.67:1. In order to find an effective, alternative procedure for the highly diastereoselective synthesis of the lactone 17a we examined the stereoselectivity of the reduction of the oxoester 15a in the presence of selected metal salts.…”

Section: Chemistrymentioning

confidence: 99%

“…1. Many methods of their preparation have been reported in the literature [24][25][26][27][28][29][30][31][32][33][34][35][36]. a-Methylene-d-lactones 2 also can act as Michael acceptors, therefore it is really surprising that the data about the cytotoxic activity of these compounds are scarce and no systematic SAR investigations have been undertaken so far.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and cytotoxic evaluation of β-alkyl or β-aryl-δ-methyl-α-methylene-δ-lactones. Comparison with the corresponding γ-lactones

Albrecht

Wojciechowski

Albrecht

et al. 2010

European Journal of Medicinal Chemistry

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Section: Chemistrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis and cytotoxic evaluation of β-alkyl or β-aryl-δ-methyl-α-methylene-δ-lactones. Comparison with the corresponding γ-lactones

Albrecht

Wojciechowski

Albrecht

et al. 2010

European Journal of Medicinal Chemistry

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“…1 In this context, paraconic acids (bearing a carboxylic acid function at the position b to the carbonyl, see Scheme 1), constitute an important class of c-butyrolactones that showed antitumor and antibiotic activies. 2 Due to the important biological activities of paraconic acids, several methods have been described for the synthesis of natural products containing b-carboxylated c-butyrolactones, including a variation of the Perkin-Fittig condensation, 3 multicomponent reactions, 4 ring-closing metathesis of two electron deficient olefins, 5 free-radical-mediated conjugate additions, 6 and aldol reactions of dioxanes.…”

Section: Introductionmentioning

confidence: 99%

Cerium metal- mediated Reformatsky-type reaction with ethyl bromosuccinate for the synthesis of novel paraconic acid analogs

Rodrigues

Nardini

Constantino

et al. 2012

Tetrahedron Letters

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a b s t r a c tThe treatment of cerium metal with ethyl bromosuccinate (1) forms the stabilized organolanthanoid intermediate (2), which reacts with carbonyl compounds in a Reformatsky-type reaction, under mild conditions, to produce functionalized c-substituted paraconic acids (4) in good yields.Ó 2012 Elsevier Ltd. All rights reserved.The synthesis of c-butyrolactones is important not only because they occur widely in nature, but also because they constitute a particularly useful class of synthons of numerous compounds possessing biological activies. 1 In this context, paraconic acids (bearing a carboxylic acid function at the position b to the carbonyl, see Scheme 1), constitute an important class of c-butyrolactones that showed antitumor and antibiotic activies. 2 Due to the important biological activities of paraconic acids, several methods have been described for the synthesis of natural products containing b-carboxylated c-butyrolactones, including a variation of the Perkin-Fittig condensation, 3 multicomponent reactions, 4 ring-closing metathesis of two electron deficient olefins, 5 free-radical-mediated conjugate additions, 6 and aldol reactions of dioxanes. 7The Reformatsky reaction in its original form uses a-halo esters as substrates to form the stabilized zinc enolates which will be added to carbonyl compounds generating b-hydroxy esters. This is a well-known synthetic methodology, with widespread use in a number of multistep syntheses. 8 Many other metals have been used in Reformatsky-type reactions, such as cerium, 9-11 magnesium, 12 nickel, 13 lithium, 14 and mischmetal 15 to allow the use of milder reaction conditions or obtaining better yields.More recently, however, Fukuzawa and co-workers 9 have demonstrated that b-halo esters can also be used in a kind of homoReformatsky reaction, because the anion in the b-position can also be stabilized, particularly if zinc is replaced by certain metals such as cerium or samarium. In these cases, due to the relative position of the groups, c-lactones are obtained instead of hydroxy-esters.We have thus decided to study the synthesis of paraconic acids through a Reformatsky-type reaction of ethyl bromosuccinate with carbonyl compounds mediated by cerium, which could stabilize the anion both as an enolate and as a complex with the b-carbonyl ester group (Scheme 1).The reaction as depicted in Scheme 2 was performed with ethyl bromosuccinate, cerium metal, and several different carbonyl substrates. Diols 5 form as by-products probably through free radical dimerization 8,16 of the carbonyl substrates. The results are summarized in Table 1. 17 0040-4039/$ -see front matter Ó

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“…For a living radical system, all chains are initiated at the same time and grow at approximately the same rate, as a consequence of the growing chains experience the same exchange in monomer concentrations (13). Lactones are present in a large variety of natural products and exhibit interesting biological properties (14). Natural insect feeding deterrents are one group of natural products considered to be useful tools to manipulate insect pest populations.…”

Section: Introductionmentioning

confidence: 99%

Homo‐ and Copolymerization of Phenacyl Methacrylate via the Atom Transfer Radical Polymerization Method

Demirelli

Çoşkun

2007

Journal of Macromolecular Science, Part A

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The homo-and copolymers via atom transfer radical (co)polymerization (ATRP) of phenacyl methacrylate (PAMA) with methyl methacrylate (MMA) and t-butyl methacrylate (t-BMA) was performed in bulk at 908C in the presence of ethyl 2-bromoacetate, cuprous(I)bromide (CuBr), and 2,2 0 -bipyridine. The polymerization of PAMA was carried out at 70, 80, and 1008C. Also, free-radical polymerization of PAMA was carried out at 608C. Characterization using FT-IR and 13 C-NMR techniques confirmed the formation of a five-membered lactone ring through ATRP. The in situ addition of methylmethacrylate to a macroinitiator of poly(phenacyl methacrylate) [Mn ¼ 2800, Mw/Mn ¼ 1.16] afforded an AB-type block copolymer [Mn ¼ 13600, Mw/Mn ¼ 1.46]. When PAMA units increased in the living copolymer system, the Mn values and the polydispersities were decreased (1.1 , Mw/Mn , 1.79). The monomer reactivity ratios were computed using Kelen-Tüdös (K-T), Fineman-Ross (F-R) and Tidwell-Mortimer (T-M) methods and were found to be r 1 ¼ 1.17; r 2 ¼ 0.76; r 1 ¼ 1.16; r 2 ¼ 0.75 and r 1 ¼ 1.18; r 2 ¼ 0.76, respectively (r 1 ¼ is monomer reactivity ratio of PAMA). The initial decomposition temperatures of the resulting copolymers were measured by TGA. Blends of poly(PAMA) and poly(MMA) obtained via the ATRP method have been characterized by differential thermal and thermogravimetric analyses.

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Advances in the Synthesis of α-Methylenelactones

Cited by 148 publications

References 0 publications

Synthesis and cytotoxic evaluation of β-alkyl or β-aryl-δ-methyl-α-methylene-δ-lactones. Comparison with the corresponding γ-lactones

Synthesis and cytotoxic evaluation of β-alkyl or β-aryl-δ-methyl-α-methylene-δ-lactones. Comparison with the corresponding γ-lactones

Cerium metal- mediated Reformatsky-type reaction with ethyl bromosuccinate for the synthesis of novel paraconic acid analogs

Homo‐ and Copolymerization of Phenacyl Methacrylate via the Atom Transfer Radical Polymerization Method

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