Total Synthesis of (-)-Chokol A by an Asymmetric Domino Michael Addition-Dieckmann Cyclization
作者:Ulrich Groth、Christian Kesenheimer、Paul Kreye
DOI:10.1055/s-2006-949653
日期:2006.9
A convergent and asymmetric total synthesis of (-)- chokol A was accomplished in six steps starting from the a,b-unsat- urated ester (E)-9 in an overall yield of 27% with an enantiomeric excess of 95%. The key step of this synthesis is the asymmetric tandem conjugate addition-Dieckmann cyclization of the higher- order cuprate 8 derived from vinyl bromide 7 with the a,b-unsatur- ated ester (E)-9.
(-)-chokol A 的收敛和不对称全合成从 a,b-不饱和酯 (E)-9 开始,分六个步骤完成,总产率为 27%,对映体过量为 95%。该合成的关键步骤是衍生自乙烯基溴 7 的高级铜酸盐 8 与 a,b-不饱和酯 (E)-9 的不对称串联共轭加成 - Dieckmann 环化。