The Preparation of Dimethyl α -Hydroxyphosphonates and the Chemical Shift Non-Equivalence of Their Diastereotopic Methyl Ester Groups

Abstract

Dimethyl α -hydroxyalkyl-, α -hydroxybenzyl-, α -hydroxyfurfuryl-, and α -hydroxy-α -thienylmethyl-phosphonates have been prepared in good yield by the alumina-catalyzed reaction of dimethyl phosphite with the corresponding alkanals, aryl aldehydes (or aryl methyl ketones), furfuraldehyde, and 2- or 3-thiophenecarboxaldehyde, respectively, thus confirming the general utility of this synthetic procedure. The ¹H and ¹³C nmr spectra of the products exhibit characteristic chemical shift non-equivalence of the diastereotopic methyl ester groups, for which a tentative order of non-equivalence is reported and discussed.

Keywords:

• α-Hydroxyphosphonate
• benzyl
• diastereotopic
• furfuryl
• NMR
• thienyl

ACKNOWLEDGMENTS

We thank Mr John Crowder for assistance with the recording of NMR spectra and Mr Stephen Boyer for microanalysis.

Notes

^aData from Ref. 16 shown for comparison.