Synthesis of α-amino phosphonates
A simple, efficient, quinine-catalyzed, enantioselective hydrophosphonylation of N-Boc protected imines with diethyl poshphite gives enantiomerically enriched α-amino phosphonates in good yields.
D. Pettersen, M. Marcolini, L. Bernardi, F. Fini, R. P. Herrera, V. Sgarzani, A. Ricci, J. Org. Chem., 2006, 71, 6269-6272.
A low catalyst loading of a chiral tethered bis(8-quinolinolato) (TBOx) aluminum(III) complexe effectively catalyzes the addition of phosphites to aldehydes and aldimines to give enantioenriched α-hydroxy and α-amino phosphonates in high yields and enantioselectivities.
J. P. Abell, H. Yamamoto, J. Am. Chem. Soc., 2008, 130, 10521-10523.
A chiral thiourea catalyzes the highly enantioselective hydrophosphonylation of a wide range of N-benzyl imines. Subsequent deprotection by hydrogenolysis provides access to free α-amino phosphonic acids in highly enantioenriched form.
G. D. Joly, E. N. Jacobson, J. Am. Chem. Soc., 2004, 126, 4102-4103.
A three-component reaction of nitro compounds, carbonyl compounds, and phosphites in the presence of indium in dilute aqueous HCl enables a high-yielding synthesis of α-amino phosphonates at room temperature. This one-pot conversion consists of reduction of nitro compounds to amines, formation of imines, and hydrophosphonylation.
B. Das, G. Satyalakshmi, K. Suneel, K. Damodar, J. Org. Chem., 2009, 74, 8400-8402.
Treatment of N-tosyl aldimines with dialkyl trimethylsilyl phosphites at 0 °C in the presence of iodine as a catalyst afforded the corresponding sulfonamide phosphonates in excellent yields in short reaction times.
B. Das, P. Balasubramanyam, M. Krishnaiah, B. Veeranjaneyulu, G. C. Reddy, J. Org. Chem., 2009, 74, 4393-4395.
A new, very mild, efficient and simple method for the preparation of tertiary α-amino phosphonates is reported. The reaction of an aldehyde, a secondary amine and trialkylphosphite in ethereal solution of lithium perchlorate (LPDE) at ambient temperature gives the desired product in high yields.
N. Azizi, M. R. Saidi, Tetrahedron, 2003, 59, 5329-5332.