Nitrone synthesis

Ade, A., Cerrada, F., Contel, M., Laguna, M., Merino, P. and Tejero, T. (2004) Organometallic gold(III) and gold(I) complexes as catalysts for the 1,3-dipolar cycloaddition to nitrones synthesis of novel gold-nitrone derivatives. Journal of Organometallic Chemistry, 689(10), 1788-1795. 

Vallee, Y. The reaction of propiolate acetylides with nitrones. Synthesis of y-amino-a,/ -ethy-lenic acid derivatives. Tetrahedron Lett. 1997,... 

Konno T, Moriyasu K, Ishihara T. A remarkable access to y-fluoroalkylated propargylamine derivatives or fluoroalky-lated dihydroisoxazoles via the reaction of fluoroalkylated acetylides with various nitrones. Synthesis 2009 1087 1094. 

Other approaches to (36) make use of (37, R = CH ) and reaction with a tributylstannyl allene (60) or 3-siloxypentadiene (61). A chemicoen2ymatic synthesis for both thienamycia (2) and 1 -methyl analogues starts from the chiral monoester (38), derived by enzymatic hydrolysis of the dimethyl ester, and proceeding by way of the P-lactam (39, R = H or CH ) (62,63). (3)-Methyl-3-hydroxy-2-methylpropanoate [80657-57-4] (40), C H qO, has also been used as starting material for (36) (64), whereas 1,3-dipolar cycloaddition of a chiral nitrone with a crotonate ester affords the oxa2ohdine (41) which again can be converted to a suitable P-lactam precursor (65). 

The preparation of isoxazolidine derivatives was first reported by Bodforss in 1918 (18CB192). The major synthesis of isoxazolidines involves the cycloaddition of nitrones with alkenes, and isoxazolidines have also enjoyed an increasing use as key intermediates in the synthesis of natural products and other heterocycles (79ACR396, 1892CB1498, 1892CB3291, 1882CB2105). 

Reactions offluorinated dipoles. In recent years, much effort has been devoted to the preparation of tnfluoromethyl-substituted 1,3-dipoles with the goal of using them to introduce trifluoromethyl groups into five-membered nng heterocycles Fluorinated diazoalkanes were the first such 1,3-dipoles to be prepared and used in synthesis A number of reports of cycloadditions of mono- and bis(tnfluo-romethyl)diazomethane appeared prior to 1972 [9] Other types of fluonne-substi-tuted 1,3-dipoles were virtually unknown until only recently However, largely because of the efforts of Tanaka s group, a broad knowledge of the chemistry of tnfluoromethyl-substituted nitrile oxides, nitnle imines, nitnle ylides, and nitrones has been accumulated recently... 

Nitrones are among the most highly studied and useful reagents for the synthesis of five-membered-nng heterocycles. The first fluonnated nitrone, N-methyl-C-(trifluoromethyl)nitrone, was prepared recently and used to introduce Irifluoromethyl groups into such heterocycles... 

Formation of functionalized cyclic nitrones via a new reaction intermediate, nitrosoketene, and its development for the synthesis of nonproteinogenic amino acids 99YGK116. 

Application in organic synthesis of optically active isoxazolidones obtained by asymmetric cycloaddition of nitrones with allenes 97T403. 

The development of metal-catalyzed asymmetric 1,3-dipolar cycloaddition reactions is probably going to continue during the next decade. High level of control of the reactions of nitrones has been obtained, and for these reactions one of the next challenges is to explore new substrates that are designed for application in synthesis. The development of metal-catalyzed asymmetric reactions of the other... 

Tohssell, K. B. G. Nitrile Oxides, Nitrones and Nitronates in Organic Synthesis] VCH, Weinheim, 1988. 

The conversion of a primary or secondary nitro alkane 1 to a carbonyl compound 3 via an intermediate nitronate 2 is called the Nef reaction. Since carbonyl compounds are of great importance in organic synthesis, and nitro alkanes can on the other hand be easily prepared, the Nef reaction is an important tool in organic chemistry. 

The required nitro compounds are easy to prepare, and are useful building blocks for synthesis. Treatment with an appropriate base—e.g. aqueous alkali—leads to formation of nitronates 2. Various substituted nitro compounds, such as nitro-ketones, -alcohols, -esters and -nitriles are suitable starting materials. 

Several approaches based on nitro-aldol for the synthesis of amino sugars have been reported Alumina-catalyzed reaction of methyl 3- nitropropanoate with O-benzyl-o-lactaldehyde gives the o-ribo-nitro-aldol fanti, and isomeri in 63% yield, which is converted into L-dannosamine fsee Secdon 3 3 Jager and coworkers have reported a short synthesis of L-acosamine based on the stereoselective nitro-aldol reaction of 2-O-benzyl-L-lactaldehyde with 3-nitropropanal dimethyl acetal as shovm in Scheme 3 10 The stereoselecdve nitro-aldol reacdon is carried ont by the silyl nitronate approach as discussed in Secdon 3 3... 

Mosher and coworkers have adopted this strategy for the enandoselecdve synthesis of 2,3-thdeoxy-3-nitro-furanosides and pyranosides using chirM nitronate dianions, as shown in Eq. 5.5."... 

Crozet and co-workers have used Spj l reactions for synthesis of new heterocycles, which are expected to be biologically active fsee iilso Section 7 3, which discusses synthesis of alkenesi For example, 2-chloromethyl-5-nitroimidazole reacts v/ith theanionof 2-nitropropane to give 2-isopropylidene-5-nitroimida2ole It is formed via C-alkyladon of the nitronate ion followed by eliminadon of HNCk fEq 5 33 Other derivadves of nitroimidazoles are idso good substrates for Spj ... 

Reports on total synthesis of naniral products using nitrones papers are as follows marine alkaloid lepadiformine fRef 92 and fi-lactam antibiotics fRef 93, ... 

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