Stereoselective synthesis of β-functionalized α-aminophosphonates via aziridinium ions

Towards Convenient Precursors for α -Phosphonylated Aziridinium Ions

“…95% of the 2-mesyloxyphosphonate (1S,2R)-23 (δ 31 P = 23.5 ppm) was obtained when phosphonate (1R,2S)-19a was subjected to mesylation with mesyl chloride in toluene at 0 • C, ammonium salts were quickly washed out with cold water, and the resulting mixture was left at room temperature for 48 h. Undoubtedly, the 1-mesyloxyphosphonate (1R,2S)-22 was produced first, and it was later transformed into the 2-mesyloxyphosphonate (1S,2R)-23 in a similar manner as described earlier. 3 However, after chromatographic purification of a 50:50 mixture of Downloaded by [Heriot-Watt University] at 18:08 03 January 2015 chlorophosphonates (1S,2R)-20 and (1S,2S)-21 prepared from (1S,2R)-23, it appeared that they were contaminated with two other phosphonates, namely the starting 1-hydroxyphosphonate (1R,2S)-19a (δ 31 P = 25.1 ppm) (ca. 2%) and the 2-hydroxyphosphonate (1S,2R)-24 (δ 31 P = 29.7 ppm) (ca.…”

“…1 Recently, we have demonstrated that the transformation of the readily available dimethyl (1R*,2S*)-2-(N,N-dibenzylamino)-1-hydroxy-2-phenylethylphosphonate 2 (1R*,2S*)-1 into 2-substituted dimethyl (1S*,2R*)-1-(N,N-dibenzylamino)-2-phenylethylphosphonates (1S*, 2R*)-3 could be accomplished in good yields and also occurred via aziridinium ion 2 (Scheme 1). 3 It would be interesting to investigate the scope of this reaction. In this article, we report on the synthesis of 1-Omesylates of the 2-(N,N-dibenzylamino)-1-hydroxyethylphosphonates 4 (R = H, i-Pr, Bn) and on their reaction with tetraethylammonium provide N,N-dibenzylaminoacetaldehyde 9, 5 which was immediately reacted with dimethyl or diethyl phosphites in the presence of catalytic amounts of triethylamine to afford racemic dimethyl or diethyl 2-(N,N-dibenzylamino)-1-hydroxyethylphosphonates 10a or 10b in 79% and 74% yield, respectively.…”

“…7 It was further supported by our studies on phosphonylation of N,Ndibenzyl-L-phenylglycinal. 3 Downloaded by [Heriot-Watt University] at 18:08 03 January 2015 SCHEME 4…”

Chemistry of Aminophosphonic Acids and Phosphonopeptides

“…Another efficient synthesis of 1,2-diamino-, 1-amino-2-hydroxy-, and 1-amino-2-chloro-2-phenylethylphosphonates 73-76 utilizes the formation of an aziridinium ion from dimethyl (1R Ã ,2S Ã )-2-(N,N-dibenzylamino)-1-hydroxy-2-phenylethylphosphonate 72 and its reactions with various nucleophiles (Scheme 5.32) [141].…”

Synthesis of new chiral amino ether derivatives: synthetic application of meso aziridinium ions prepared from β-amino alcohols

“…Mp >300°C; ½a 25 D ¼ À91 (c 0.12, CH 3 OH); IR (KBr): 3082,2934,1620,1589,1506,1433,1267,1234,1084,810,773,748, 694 cm À1 . 6,25.0,26.7,28.3,31.3,50.5,67.3,77.7,115.8,116.9,117.3,117.6,123.0,124.0,125.2,125.4,126.2,126.9,127.9,128.0,129.2,129.5,130.2,134.3,134.6,151.5,154.0. MS (EI): m/z 451 (m + ).…”