Abstract
The imide-amide rearrangement of cyclic phosphorirnidates 1 leads to the formation of phosphoramidates 3, either thermally (> 180°C) or by the action of a Lewis acid (BF3 OEt2, 60°C)1. In an attempt to develop a synthetic pathway to β aminoalcohols based on this rearrangement, we have thoroughly studied the influence of the structure of the reactants on the Lewis acid catalysed rearrangement. This study brought some insight into the mechanism of this particular reaction, namely the identification of a new polymeric structure 2. not yet described, which is converted into 3 by thermolysis2. The formation of 2 at rt was followed by 3 P NMR. In the case of R′˭ Ph, the reactivity observed for R2N was: i-Pr2N > Pyrrolidine > n-Bu2N For R2=i-Pr2, the observed R′ group effect was: Bn > 4-NO2Bn > Ph. No reaction was observed for R′ ˭ Ts, n-Oct. In the case of the groups R′ ˭ Bn and R2=i Pr2 the Lewis acid effect was also studied: BF3OEt2, BF3MeOr-Bu, Sc(OTf)3 or CITi(Oi-Pr)3 or Me2SnCl2.