Enantioselective Total Syntheses of (−)-FR901483 and (+)-8-epi-FR901483
摘要:
The enantioselective total syntheses of the potent immunosuppressant FR901483 (1) and its 8-epimer (47) have been accomplished. Our approach features the use of building block 6 as the chiron, the application of the one-pot amide reductive bis-alkylation method to construct the chiral aza-quaternary center (dr = 9:1), regio- and diaster-eoselective intramolecular aldol reaction to build the bridged ring, and RCM to form the 3-pyrrolin-2-one ring.
A formal enantioselective total synthesis of the potent immunosuppressant FR901483 (1) has been accomplished. Our approach features the use of chiron 6 as the starting material, the application of the one-pot amide reductive bisalkylation method to construct the chiral aza-quaternary center (dr = 9:1), regio- and diastereoselective intramolecular aldol reaction to build the bridged ring, and ring closing metathesis to form the 3-pyrrolin-2-one ring.
Mild Metal-Free Hydrosilylation of Secondary Amides to Amines
作者:Pei-Qiang Huang、Qi-Wei Lang、Yan-Rong Wang
DOI:10.1021/acs.joc.6b00572
日期:2016.5.20
tetrahydro-5-oxo-2-furaneamides yielded 5-(aminomethyl)dihydrofuran-2(3H)-ones in a racemization-free manner. The latter were converted in one pot to N-protected 5-hydroxypiperidin-2-ones, which are building blocks for the synthesis of many natural products. Further elaboration of an intermediate led to a concise four-step synthesis of (−)-epi-pseudoconhydrine.
Tf 2 O的酰胺活化与B(C 6 F 5)3催化的氢硅烷基化与TMDS的结合构成了一种在温和条件下将一阶仲酰胺还原为胺的方法。该方法对减少多种类型的底物显示出广泛的适用性,并且对于许多敏感的官能团显示出良好的相容性和优异的化学选择性。从另一种合成方法获得的多官能化的α,β-不饱和酰胺的还原以及C–H官能化的产物可产生相应的胺,收率好至极好。化学选择性还原对映体纯的(ee> 99%)四氢-5-氧代-2-呋喃酰胺,生成5-(氨基甲基)二氢呋喃-2(3 H)-以无消旋的方式进行。将后者在一个罐中转化为N保护的5-羟基哌啶-2-酮,这是合成许多天然产物的基础。进一步精制中间体导致(-)- Epi- pseudoconhydrine的简洁的四步合成。
Enantioselective Total Syntheses of (−)-FR901483 and (+)-8-<i>epi</i>-FR901483
The enantioselective total syntheses of the potent immunosuppressant FR901483 (1) and its 8-epimer (47) have been accomplished. Our approach features the use of building block 6 as the chiron, the application of the one-pot amide reductive bis-alkylation method to construct the chiral aza-quaternary center (dr = 9:1), regio- and diaster-eoselective intramolecular aldol reaction to build the bridged ring, and RCM to form the 3-pyrrolin-2-one ring.