New Applications of Dipolar Cycloaddition Chemistry Toward the Synthesis of Heterocycles (original) (raw)
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European Journal of Organic Chemistry, 2006
Nitrones and azomethine ylides formed by condensation of chiral 2-formyl-perhydro benzoxazines and N-substituted hydroxylamines or cyclic α-amino acids cyclize intramolecularly yielding polycyclic isoxazolidine or pyrrolidine derivatives, respectively, with total diastereoselectivity. On the con- [a] thol. These compounds cyclized intramolecularly with the inactivated double bond placed on the nitrogen atom of the heterocycle.
Cycloadditions of highly functionalized C6-synthons to cyclic nitrones
Tetrahedron, 1997
The 1,3-dipolar cycloaddition of cyclic nitrones to several C6 ct,[~-unsaturated esters and lactones with different functionalities has been studied. All these olefins have shown high stereoselectivity, with a predominance of the exo or endo transition state for the cis or trans dipolarophiles, respectively. The antifacial approach is favoured in the reactions with 7-substituted hexenolides and also with the substituted nitrone 21. © 1997 Elsevier Science Ltd.
Tetrahedron Letters, 1999
The preparation of novel 3-(4-methyl-2,6,7-trioxabicyclo[2.2.2]octyl)-A2-isoxazolines 2 via nitrile oxide cycloaddition chemistry is described. The target compounds were produced in moderate to good yields using only 2.2 equivalents of alkene and without the need for slow addition of reagents. Cycloaddition reactions were conducted using modified Mukaiyama conditions that included a convenient dehydration reagent which significantly simplified product isolation.
The Journal of organic chemistry, 2015
An efficient method for synthesizing different functionalized azabicyclo[X.Y.0]alkanone amino acid derivatives has been developed employing electrophilic transannular cyclizations of 8-, 9- and 10-member unsaturated macrocycles to form fused 5,5-, 6,5-, 7,5- and 6,6-fused bicylic amino acids, respectively. Macrocycles were obtained by a sequence featuring peptide coupling of vinyl, allyl, homoallyl, and homohomoallyl-glycine building blocks followed by ring closing metathesis. X-ray crystallographic analyses of the 8-, 9- and 10-member macrocycle lactam starting materials as well as several bicyclic amino acid products provided insight into their conformational preferences as well as the mechanism for the diastereoselective formation of specific azabicycloalkanone amino acids by way of transannular iodolactamization reactions.
Journal of Heterocyclic Chemistry, 2007
magnified imageCycloadditions of C,N‐diarylnitrones to β‐nitrostyrenes occurred to yield two diastereoisomeric cycloadducts, the 3,4‐trans‐4,5‐trans substituted isoxazolidine derivatives being formed selectively as the major products. These were characterised by spectroscopic and X‐ray data. Conformational studies were carried out by X‐ray crystallography and Molecular Modelling.
The Journal of organic chemistry, 2008
New isoxazolidines were synthesized in good to excellent yields by 1,3-dipolar cycloaddition of N-vinylamide dipolarophiles and nitrones. Strikingly, solvent-free conditions gave high conversion and yields, shortened reaction time, and minimized degradation products. N-Vinyloxazolidin-2-one and its analogues used in these cycloaddition reactions were conveniently prepared in excellent yields by a modified version of Buchwald's one-step copper-catalyzed vinylation using vinyl bromide. From the adducts, a two-step access to various unsymmetric aspartate derivatives was also described. (1) For reviews of cycloaddition of nitrones, see: (a) Padwa, A., Ed. In 1,3-Dipolar Cycloaddition Chemistry; Wiley-Interscience: New York, 1984; Vols. 1-2. (b) DeShong, P.; Lander, S. W., Jr.; Leginus, J. M.; Dicken, C. Mita, N.; Imai, Y.; Nishimura, T.; Kiyotani, T.; Yamasaki, M.; Shiro, M.; Morita, N.; Okamoto, I.; Takeya, T.; Ishibashi, H.; Sakamoto, M. Tetrahedron 2006, 62, 12227. (b) Ashizawa, T.; Ohtsuki, N.; Miura, T.; Ohya, M.; Shinozaki, T.; Ikeno, T.; Yamada, T. Heterocycles 2006, 68, 1801. (5) Chiacchio, U.; Corsaro, A.; Gumina, G.; Romeo, R. J. Org. Chem. 1999, 64, 9322. (6) Ishizuka, T.; Matsunaga, H.; Iwashita, J.; Arai, T.; Kunieda, T. Heterocycles 1994, 37, 715. (7) Nguyen, T. B.; Gaulon, C.; Chapin, T.; Tardy, S.; Tatibouët, A.; Rollin, P.; Dhal, R.; Martel, A.; Dujardin, G.
Synthesis, 2017
This review summarizes the trends in the formation of complex or not so complex heterocyclic structures through 1,3-dipolar cycloadditions of azomethine ylides. Diastereo- and enantioselective processes as well as non-asymmetric cycloadditions constitute very important synthetic tools for achieving these compounds. This review covers the literature from 2015 through 2016 and organizes the research in terms of biologically important heterocycles and natural products from cascade 1,3-dipolar cycloadditions of azomethine ylides to the simpler forms of 1,3-dipolar cycloaddition.1 Introduction2 Synthesis of Spirooxindoles3 Synthesis of Spiropyrrolidines4 Synthesis of Spiropiperidines and Piperidines5 Synthesis of Pyrrolidines and Fused Pyrrolidines6 Synthesis of Pyrrolizidines and Indolizidines7 Synthesis of Quinolone and Isoquinolines8 Conclusions