Department of Chemistry, Columbia University, New York, New York 10027, USA.
Org Lett. 2012 Sep 21;14(18):4890-3. doi: 10.1021/ol302221s. Epub 2012 Sep 5.
An efficient synthesis of the C(1)-C(9) fragment of fludelone has been developed. The key step is a tandem silylformylation-crotylsilylation/Tamao oxidation sequence that establishes the C(5) ketone, the C(6), C(7), and C(8) stereocenters, and the C(9) alkene in a single operation from a readily accessed starting material. The stereochemical outcome at C(6) depends critically on the development of an "aprotic" Tamao oxidation, which leads to a reversal in the intrinsic diastereoselectivity observed using "standard" Tamao oxidation conditions.
已经开发出一种高效合成氟代酮的 C(1)-C(9)片段的方法。关键步骤是串联的硅基甲酰化-烯丙基硅基化/Tamao 氧化序列,该序列可从易得的起始原料中单一操作构建 C(5)酮、C(6)、C(7)、C(8)立体中心和 C(9)烯烃。C(6)处的立体化学结果取决于“非质子”Tamao 氧化的发展,这导致与使用“标准”Tamao 氧化条件观察到的固有非对映选择性相反。