DAST mediated preparation of β-fluoro-α-aminophosphonates

Preparation and characterization of α-fluorinated-γ-aminophosphonates

“…All moisture sensitive reactions were carried out under argon atmosphere using oven-dried glassware. Reaction temperatures below 0 8C were performed using a cooling bath (liquid N 2 /hexane or CO 2 /isopropanol [16]. The NMR data of all the synthesized N,N-dibenzylamino alcohols were in good agreement with the reported data from an alternative synthesis [16,26,27].…”

“…Carbonyl compounds 2a-f were prepared from aamino acids (a-L-alanine, b-L-valine, c-L-leucine, d-L-isoleucine, e-Lphenylalanine, f-D-phenylglycine) in a three step procedure [16]. N,N-dibenzylamino aldehydes 2a-f were then treated with lithiated carbanion generated by addition of n-BuLi to tetraethyl fluoromethylenebisphosphonate 1 at À78 8C in dry THF.…”

“…N,N-dibenzylamino alcohols were next converted to corresponding N,N-dibenzylamino aldehydes 2a-f [16]. Carbonyl compounds 2a-f after extraction and evaporation of solvents, were sufficiently pure to be used directly in the HWE reaction.…”

Efficient synthesis of dipeptide analogues of α-fluorinated β-aminophosphonates

“…In our previous studies, the Pudovik reaction worked with satisfactory yield and diastereoselectivity [30]. Unfortunately, we were not able to isolate the pure anti-isomer in every case.…”

“…Our previous studies have shown that the regioselectivity of the nucleophilic fluorination of amino alcohols can be controlled depending on the fluorinating reagent used [30,31]. This work presents the optimization of nucleophilic fluorination conditions.…”