Asymmetric catalysis in carbon-phosphorus bond formation

✍ Scribed by Hans Wynberg; Ab A. Smaardijk

• Book ID: 104226373
• Publisher: Elsevier Science
• Year: 1983
• Tongue: French
• Weight: 128 KB
• Volume: 24
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)94232-1

✦ Synopsis

o-Nitrobenzaldehyde reacts smoothly with dialkylphosphonates in -presence of catalytic quantities of cinchona alkaloids (e.g. quinine) to produce the a-hydroxy phosphonate esters in excellent chemical yields, with excellent enantiomeric enrichment. Chiral organophosphorous compounds are becoming increasingly important.' Since dialkyl phosphonates (1) are excellent nucleophiles it occurred to us that their well-established ability to condense with carbonyl compounds under base catalyzed* and thermal 3 conditions might be subject to catalysis by chiral amines. This proved to be the case. Thus when o-nitrobenzaldehyde4 (3.45 g, 23 nM; m.p. 43-44")5 in 75 ml dry toluene was treated with freshly distilled dimethyl phosphonate (l_R-CH3) (2.54 g; 23 nM) and 60 mg (0.18 nM) quinine was added, the