反应详情

Experiments were also conducted by reacting the following α,β-unsaturated aldehydes represented by the formula (II) as defined above, all with nitrosobenzene in the presence of the IPrCl catalyst (10-20 mol %), KOtBu and CH2Cl2 (r.t., 1-6 h) forming the corresponding N-phenylisoxazolidin-5-one derivatives in the following yields a (%, determined by 1H NMR), and then treating the N-phenylisoxazolidin-5-one derivatives with MeOH in the presence of an acid catalyst (r.t., 12 h) forming the corresponding β-amino acid ester derivatives in the following yields b (%): i) R1=3-Br-4-OTfPh and R2═H; yield a=83%; yield b=79%. ii) R1=4-CNPh and R2═H; yield a=95%; yield b=40%. iii) R1═C6F5 and R2═H; yield a=85%; yield b=72%. iv) R1=3,5-F2Ph and R2═H; yield a=88%; yield b=78%. v) R1═C4H9 and R2═H; yield a=40%; yield b=30%.