Synthesis of a-Amino Phosphonates

Fee et al. have investigated the Fewis acid-catalyzed three-component synthesis of a-amino phosphonates [73]. This was carried out in the ionic liquids [BMIM][PFg],... 

To complement the above information, a highly enantioselective synthesis of a-amino phosphonate diesters should be mentioned.164 Addition of lithium diethyl phosphite to a variety of chiral imines gives a-amino phosphonate with good to excellent diastereoselectivity (de ranges from 76% to over 98%). The stereoselective addition of the nucleophile can be governed by the preexisting chirality of the chiral auxiliaries (Scheme 2-63). 

Kaboudin, B. and Nazari, R., Microwave-assisted synthesis of 1-aminoalkyl phosponates under solvent-free conditions, Tetrahedron Lett., 2001, 42, 8211-8213 Yadav, J.S., Subba Reddy, B.V. and Madan, Ch., Montmorillonite clay-catalyzed one-pot synthesis of a-amino phosphonates, Synlett, 2001, 1131-1133. 

A BINOL-derived phosphoric acid derivative has been used as a catalyst in the enantioselective synthesis of a-amino phosphonates via hydrophosphonylation of imines with diisopropyl phosphite.82... 

Kitamura, M., Yoshimura, M., Tsukamoto, M., Noyori, R. Synthesis of a-amino phosphonic acids by asymmetric hydrogenation. Enantiomer 1996, 1, 281-303. 

In spite of the high level of interest in the asymmetric synthesis of a-amino phosphonic acids, less is known in the case of cyclic a-amino phosphonates. Although in recent years descriptions of promising pharmaceutical applications for cyclic compounds (and acylated derivatives thereof) have been published [61-64], until now no efficient general asymmetric route has been available to prepare this class of a-amino phosphonates. Several attempts at a diastereose-lective synthetic route which were made by the addition of a stoichiometric amount of chiral phosphites to cyclic imines, namely thiazolines, gave only limited diastereoselection ratios of dr=2 1 or below [75,76]. 

Three-componenta-Amino Phosphonate Synthesis. A simple and efficient synthesis of a-amino phosphonates is possible under relatively mild conditions by the reaction of aldehydes, amines, and a dialkylphosphite using samarium iodide in catalytic amounts (eq 72). ... 

For selected pioneering examples, see (a) D. Uraguchi, K. Sorimachi, M. Terada, J. Am. Chem. Soc. 2004, 126, 11804-11805. Organocatalytic asymmetric aza-Friedel-Crafts alkylation of furan. (b) T. Akiyama, H. Morita, J. Itoh, K. Fuchibe, Org. Lett. 2005, 7, 2583-2585. Chiral Br0nsted acid catalyzed enantioselective hydrophosphonylation of imines asymmetric synthesis of a-amino phosphonates. 

Kabachnik-Fields reaction is a three-component reaction between a carbonyl compound (ketone and aldehydes), an amine, and a dialkyl phosphite [144] to form a-aminoalkylphosphonates 79 (Scheme 12.26). It was first described in 1952 independently by Kabachnik [145] and Fields [ 146]. This reaction constitutes a general and effective method for the synthesis of a-amino phosphonates, which, in the last five decades, have danonstrated to be a kind of compounds of relevance. 

Therefore, a-aminophosphonic acids and their derivatives represent a synthetic goal in modem chemistry [162]. Among other approaches, Kabachnik-Fields reaction represents a straightforward method for the synthesis of a-amino phosphonates. There are a great number of reported racemic versions of Kabachnik-Fields reaction, and some examples will be only mentioned in the following, while scarce enantioselective cases will be treated in detail. 

B. C. Ranu, A. Hajra, U. Jana, Org. Lett. 1999,1,1141-1143. General procedure for the synthesis of a-amino phosphonates from aldehydes and ketones using indium(III) chloride as a catalyst. 

Z. P. Zhan, J. P. Li, Synth. Commun. 2005, 35, 2501-2508. Bismuth(III) chloride-catalyzed three- component coupling synthesis of a-amino phosphonates. 

S. Chandrasekhar, S. J. Prakash, V. Jagadeshwar, C. Narsihmulu, Tetrahedron Lett. 2001, 42, 5561-5563. Three component coupling catalyzed by TaClj-SiO synthesis of a-amino phosphonates. 

J. S. Yadav, B. V. S. Reddy, C. Madan, Synlett 2001, 1131-1133. Montmorillonite clay-catalyzed one-pot synthesis of a-amino phosphonates. 

A. K. Bhattacharya, K. C. Rana, Tetrahedron Lett. 2008,49, 2598-2601. Amberlite-IR 120 catalyzed three-component synthesis of a-amino phosphonates in one-pot. 

M. Z. Kassaee, F. Movahedi, H. Masrouri, Synlett 2009, 1326-1330. ZnO nanoparticles as an efficient catalyst for the one-pot synthesis of a-amino phosphonates. 

Mozzumdar, Catal. Sci. Technol. 2011, 1, 426 30. Application of mobilized Cu-nanoparticles as heterogeneous catalyst for the synthesis of a-amino phosphonates via A2-P coupling. 

M. V. Prisyazhnoi, I. N. Rusetskaya, N. S. Zefirov, Russ. Chem. Bull. Int. Ed. 2007, 56, 798—805. Three-component catalytic method for synthesis of a-amino phosphonates with the use of a-amino acids as amine component, (e) E. D. Matveeva, T. A. Podrugina, I. N. Kolesnikova, A. A. Borisenko, N. S. Zefirov, Russ. Chem. Bull. Int. Ed. 2009, 58, 119-125. Aminopyridines as amino components in the catalytic synthesis of a-aminophosphonates. For an example of sUica gel-immobilized aluminum phthalocya-nine complex, see (f) E. D. Matveeva, M. V. Shuvalov,... 

N. S. Zefirov, Russ. Chem. Bull. Int. Ed. 2011, 60, 242-247. Sihca gel-immobiUzed aluminum phthalocyanine complex as a heterogeneous catalyst for the synthesis of a-amino phosphonates. 

Uncatalyzed one-pot diastereoselective synthesis of a-amino phosphonates under solvent-free conditions, (b) G. D. Tibhe, V. Labastida-Galvan, M. Ordonez, Rapid Common. Mass Spectrom. 2011, 25, 951-959. Study of the fragmentation pathway of a-aminophosphonates by chemical ionization and fast atom bombardment mass spectrometry, (c) J. L. Viveros-Ceballos, C. Cativiela, M. Orddnez, Tetrahedron Asymmetry 2011, 22, 1479-1484. One-pot three-component highly diastereoselective synthesis of isoindohn-l-one-3-phosphonates under solvent and catalyst free-conditions. (d) G. D. Tihhe,... 

Application of IL also used in the synthesis of a-amino phosphonates as a three-component reaction of aldehydes, amine, and diethyl phosphite-catalyzed... 

Peipei S, Xin Y, Zhixin H (2006) One-pot synthesis of a-amino phosphonates in chloroalu-minate-based ionic liquid. J Chem Res 4 240-241... 

Xu F, Luo Y, Deng M, Shen Q (2003) One-pot synthesis of a-amino phosphonates using samarium diiodide as a catalyst precursor. Eur J Org Chem 24 47284730... 

Jeong et al. reported cadmium perchlorate hydrate [CdlClOja xHjO] as a novel, expeditious catalyst for the three-component synthesis of a-amino-phosphonates via a one-pot reaction of an amine, a carbonyl (aldehyde/ ketone) and a H-phosphonate diester e.g. dimethylphosphite/diethylphos-phite) in open air in the absence of any solvent, with high yields (Scheme 17.15). This new methodology is the first example of a cadmium perchlorate hydrate-catalysed Kabachnik-Fields reaction. ... 

A new, highly flexible, solvent free procedure has been described by Vahdat et al. for synthesis of a-hydroxy phosphonates (110) (Scheme 37). In the presence of a catalytic amount of oxalic add, trimethyl phosphite reacted with aldehydes to yield the corresponding coupled products in good yields (83-98%). The same procedure has been successfully applied for synthesis of a-amino phosphonates. 

Das, B., Satyalakshmi, G., Suneel, K., and Damodar, K. (2009). Organic reactions in water A distinct novel approach for an efficient synthesis of a-amino phosphonates starting directly from nitro compounds. 7. Org. Chem., 74, 8400-8402. 

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