practical total synthesis of both enantiomers of epoxyquinols A and B has been developed. Key reactions are the chromatography-free preparation of an iodolactone by using acryloyl chloride as dienophile in the Diels–Alder reaction of furan, the lipase-mediated kinetic resolution of a cyclohexenol derivative, and a modified procedure for α-iodonation of a cyclohexenone.
An efficient synthesis of ECH, epoxyquinols A and B, and two bioactive analogs EqM and RKTS-33 has been completed starting from (−)-shikimic acid. Rapid establishment of the desired epoxyquinol core is facilitated through a key allylic oxidation with high stereoselectivity, which is achieved by fine tuning the cyclohexene substrate structure and reaction conditions.
从 (-)-莽草酸开始,已经完成了 ECH、环氧喹啉 A 和 B 以及两种生物活性类似物 EqM 和 RKTS-33 的有效合成。通过具有高立体选择性的关键烯丙基氧化促进所需环氧喹啉核的快速建立,这是通过微调环己烯底物结构和反应条件来实现的。
Novel non-peptide inhibitors targeting death receptor-Mediated apoptosis
作者:Hideaki Kakeya、Yasunobu Miyake、Mitsuru Shoji、Satoshi Kishida、Yujiro Hayashi、Takao Kataoka、Hiroyuki Osada
DOI:10.1016/j.bmcl.2003.08.003
日期:2003.11
We have previously reported that ECH, (2R, 3R, 4S)-2,3-epoxy-4-hydroxy-5-hydroxymethyl-6-(1E)-propenyl-cyclohex-5-en-1-one inhibits Fas-mediated apoptosis by blocking self-activation of pro-caspase-8 in the death-inducing signaling complex (DISC). A series of ECH derivatives were asymmetrically synthesized via key synthetic intermediates obtained from lipase-catalyzed kinetic resolution. Inhibitory activities of the derivatives towards death receptor-mediated apoptosis both in type I and type 11 cells were investigated, revealing that novel non-peptide inhibitors, RKTS-33 and RKTS-34, are effective as ECH. (C) 2003 Elsevier Ltd. All rights reserved.
Stereoselective Total Synthesis of <i>ent</i>-EI-1941-2 and Epi-<i>ent</i>-EI-1941-2
作者:Mitsuru Shoji、Takao Uno、Yujiro Hayashi
DOI:10.1021/ol0481479
日期:2004.11.1
The first asymmetric total syntheses of ent-EI-1941-2 and epi-ent-EI-1941-2 have been accomplished, starting from a chiral epoxy iodoquinone 6, a key intermediate in our total syntheses of epoxyquinols A and B. A key step in the preparation of ent-EI-1941-2 is an intramolecular carboxypalladation via a 6-endo cyclization mode, followed by beta-hydride elimination, while carboxymercuration is a key step in the synthesis of epi-ent-EI-1941-2.
Efficient Asymmetric Synthesis of Chiral Monomer of Epoxyquinols and (-)-Phyllostine