Synthesis of (±)-branched-chain azaisonucleosides via Michael addition of 5-nitro-2,2-pentamethylene-1,3-dioxane to methyl 2-bromoacrylate

Mironiuk‐Puchalska, Ewa; Kolaczkowska, Ewa; Sas, Wojciech

doi:10.1016/s0040-4039(02)02012-9

Cited by 23 publications

(9 citation statements)

References 28 publications

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“…11 The enantioselective hydrogenation of the C-C double bond of a-haloacrylates has also been described, 12 and classical ester reduction can be performed leading to a-chlorinated, a,b-unsaturated aldehydes or allylic alcohols. This large array of reactivity has been used for the preparation of pharmaceutical drugs or for natural products synthesis such as a-amino-acids, 13 aziridines, 14 amino-alcohols, 14 nucleosides, 15 heterocycles, 16 as well as in polymer chemistry. 17 With a-bromoacrylates or a-iodoacrylates, substitution of the halogen atom can be easily mediated by transition metals (Pd 0 , Sm II ), 18,19 leading to very valuable trisubstituted alkenes of controlled configuration.…”

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confidence: 99%

Pd0-Catalyzed carbonylation of 1,1-dichloro-1-alkenes, a new selective access to Z-α-chloroacrylates

2010

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confidence: 99%

Pd0-Catalyzed carbonylation of 1,1-dichloro-1-alkenes, a new selective access to Z-α-chloroacrylates

2010

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“…The literature shows that this function is usually synthesized owing to methodologies using only stoichiometric amounts of toxic and/or expensive transition metals, or through Wittig strategies which, however, always lead to E/Z mixtures. 20 Therefore, a catalytic method was still missing and appeared to be even more important when considering that a-chloroacrylates are utilized as key synthetic intermediates in the preparation of pharmaceutical drugs as well as natural products such as a-amino acids, 21 aziridines, 22 amino alcohols, 22 nucleosides, 23 heterocycles, 24 and was also used in polymer chemistry. 25 We deliberately chose to work under an atmospheric pressure of CO, allowing the use of a simple balloon.…”

Section: Methodsmentioning

confidence: 99%

Various Entries to Vinyl Chloride Derivatives and their Applications in Total Synthesis of Natural Products

Guinchard¹,

Roulland²

2011

Synlett

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Our program of total synthesis of natural products stimulated our imagination and led us to design various methodologies to build the vinyl chloride function of our targets. The access to vinyl chlorides also offers an entry to the trisubstituted alkenes of pure configuration. Thanks to these methodologies we achieved the synthesis of complex structures such as (+)-oocydin A, a total synthesis that also led us to discover other useful new transformations.

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“…a-Halo-a,b-unsaturated acid derivatives are precursors of relevant organic derivatives such as a-halo-a,b-unsaturated ketones, 28 carboxylic acids, 29 2-haloallylic alcohols, 30 a-amino acids, 31 various heterocycles including aziridines 2,32 or trisubstituted alkenes 33 In addition, natural products or pharmaceutical drugs 34 have been prepared from these compounds.…”

Section: Synthesis Of (Z)-a-haloacrylic Acid Derivatives 9 and 10mentioning

confidence: 99%

Stereoselective Olefination Reactions Promoted by Rieke Manganese

Concellón¹,

Rodríguez‐Solla²,

Amo³

et al. 2009

Synthesis

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A study of the advantages of using manganese, an inexpensive and nontoxic metal, to perform stereoselective b-elimination reactions and to promote sequential olefination reactions of aldehydes to obtain a,b-unsaturated esters and amides is presented. Various elimination reactions, all of them characterized by occurring with complete stereoselectivity and in high yields, were performed using active manganese (Mn*) as metalating agent. This ability of manganese has been applied to develop a novel and direct synthesis of (E)-a,b-unsaturated esters or amides and (Z)-a,b-unsaturated a-halo esters and a-choroamides through a Mn*-mediated sequential olefination protocol of aldehydes with dichloro esters or amides and trihalo esters or trichloroamides, respectively.Manganese is a nontoxic 1 and inexpensive 2 metal and the reduction potential of Mn 2+ /Mn 0 system (-1.03 V) 3 is adequate to reduce an important number of organic functions. According to these properties, extensive use of manganese in organic synthesis might be expected. However, in contrast to other metals, such as lithium, magnesium, zinc, or samarium, the application of manganese in organic synthesis has been scarcely developed. Among the main reasons for this lack of development are the inability of commercially available manganese to react directly with organic compounds as consequence of its passivity, 4 mainly because of the formation of an oxide layer on its surface. To overcome the lack of reactivity of manganese metal, different procedures have been describe to obtain active manganese (Mn*) by Rieke 5 and Fürstner 6 in 1996, by Oshima 7 in 1998, and by Cahiez 8 in 1999. Since then the number of reported transformations promoted by Mn* have increased. 9 It is important to note that all these transformations take place with high selectivity. Combining the aforementioned properties of manganese (reduction potential, selectivity, low price, and toxicity) with our interest in the development of novel highly selective organic reagents, including the use of selective metals, has prompted us to develop new synthetic applications of manganese.We decided to test the ability of manganese to promote highly stereoselective elimination reactions towards the synthesis of a,b-unsaturated esters or amides, based on: (a) the use of manganese to carry out elimination reactions has not been previously reported, and (b) despite there being a large number of contributions reporting the synthesis of a,b-unsaturated esters 10,11 or amides, 11,12 some of these methods take place without complete stereoselectivity (particularly when the double bond is trisubstituted) and are either tedious (multistep procedures) or imply the use of expensive starting materials.Based on these precedents, we reported the first transformation of 2-bromo-3-hydroxy esters into a,b-unsaturated esters with complete stereoselectivity promoted by commercial manganese activated by chlorotrimethylsilane. 13 Later, we described a novel manganese-mediated olefination reaction of aldehydes to obtain (E)-...

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Synthesis of (±)-branched-chain azaisonucleosides via Michael addition of 5-nitro-2,2-pentamethylene-1,3-dioxane to methyl 2-bromoacrylate

Cited by 23 publications

References 28 publications

Pd0-Catalyzed carbonylation of 1,1-dichloro-1-alkenes, a new selective access to Z-α-chloroacrylates

Pd0-Catalyzed carbonylation of 1,1-dichloro-1-alkenes, a new selective access to Z-α-chloroacrylates

Various Entries to Vinyl Chloride Derivatives and their Applications in Total Synthesis of Natural Products

Stereoselective Olefination Reactions Promoted by Rieke Manganese

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