A Convergent Total Synthesis of the Potent Cephalostatin/Ritterazine Hybrid -25-<i>epi</i> Ritterostatin G<sub>N</sub>1<sub>N</sub>
作者:Ananda Kumar Kanduluru、Prabal Banerjee、John A Beutler、Philip L Fuchs
DOI:10.1021/jo401171q
日期:2013.9.20
The convergentsynthesis of 25-epi ritterostatin GN1N is described for the first time, starting from hecogenin acetate (HA). Stereoselective dihydroxylation employing the chiral ligand (DHQ)2PHAL was used as the key step to introduce the C25 epi-stereocenter on the north 1 segment. The title compound was obtained through a coupling reaction between the C3-keto-azide (cstat North 1) and North G.
首次描述了25- epi ritterostatin G N 1 N的会聚合成,从醋酸hecogenin (HA) 开始。采用手性配体的立体选择性二羟基化(DHQ)2 PHAL用作引入C25的关键步骤外延在北部1段-stereocenter。通过 C3-酮-叠氮化物 (cstat North 1) 和 North G 之间的偶联反应获得标题化合物。
An Efficient C−H Oxidation Protocol for α-Hydroxylation of Cyclic Steroidal Ethers
作者:Seongmin Lee、Philip L. Fuchs
DOI:10.1021/ol049712a
日期:2004.4.1
Various C-16 hydroxy steroids have been prepared with the aid of CrO3/Bu4NIO4. Out of the two possible reaction courses, transition state B is favored because of less steric interference between substrate and CrO4. Thus, C-H bonds at C-16 are oxidized selectively.