Highly diastereoselective reduction of β-ketophosphonates bearing homochiral bis(α-methylbenzyl)amine: preparation of both enantiomers of phosphogabob (GABOBP)

Synthesis of (R)- and (S)-β-hydroxyphosphonate acyclonucleosides: structural analogues of Adefovir (PMEA)

A synthetic pathway to new acyclonucleoside phosphonates, as analogues of Adefovir, is described. The reduction of an acyclonucleoside β-ketophosphonate, readily available from the nucleobase and benzylacrylate, afforded a mixture of (R)- and (S)-β-hydroxyphosphonate derivatives which was resolved. The assignment of the absolute configuration was proposed on the basis of NMR studies and was supported by molecular modelling studies.

Synthesis of syn-gamma-amino-beta-hydroxyphosphonates by reduction of beta-ketophosphonates derived from L-proline and L-serine

The reduction of γ-N-benzylamino-β-ketophosphonates 6 and 10, readily available from L-proline and L-serine, respectively, can be carried out in high diastereoselectivity with catecholborane (CB) in THF at -78 °C to produce the syn-γ-N-benzylamino-β-hydroxyphosphonates 11 and 13 as a single detectable diastereoisomer, under non-chelation or Felkin-Anh model control.

The Assignment of the Absolute Configuration of Diethyl Hydroxy- and Aminophosphonates by 1H and 31P NMR Using Naproxen as a Reliable Chiral Derivatizing Agent

The assignment of the absolute configuration of hydroxy- and aminophosphonates by their double derivatization with commercially available naproxen is presented. The correlation between the spatial arrangement around the stereogenic carbon center and the signs of the DeltadeltaRS allows determination of the absolute configuration of hydroxy- and aminophosphonates by simple comparison of the 1H and 31P NMR spectra of the (R)- and (S)-naproxen ester or amide derivatives. Extensive conformational analysis (theoretical calculations, low-temperature experiments) supported by the NMR studies of structurally diverse naproxen esters and amides of hydroxy- and aminophosphonates proved that a simplified model can be successfully used.

Asymmetric alkylation of dimethoxyphosphoryl-N-[1-(S)-alpha-methylbenzyl]acetamide enolates. Synthesis of both stereoisomers from the same source of chirality by changing the equivalents of LDA

A new methodology has been developed for the synthesis of both stereoisomers from a single chiral source.