Diastereo- and Enantioselective Synthesis of<i>syn</i>-2,3-Disubstituted 1,4-Diketones<i>via</i>Oxidative Coupling of Metalated Hydrazones
作者:Dieter Enders、Peter Müller、Daniela Klein
DOI:10.1055/s-1998-1562
日期:1998.1
An efficient diastereo- and enantioselective synthesis of syn-2,3-disubstituted 1,4-diketones 4 is described. Key step of the procedure is the oxidative coupling of the metalated SAMP/RAMP-hydrazones 2 with iodine, followed by oxidative cleavage of the dimerized bishydrazones 3 with ozone and subsequent separation of the minor meso-isomer by chromatography. The d,l-isomers of the title 1,4-diketones 4 are obtained in good overall yields (20-64%) and high diastereo- and enantiomeric excesses (de ≥ 98%, ee = 80- ≥ 95%).