Synthesis of a para-quinone macrolactam related to geldanamycin by ring closing metathesis
作者:Aude Lemarchand、Thorsten Bach
DOI:10.1016/j.tet.2004.06.147
日期:2004.10
macrocyclic 2,5-di-iso-propoxy-4-methoxyanilide 22 was prepared. The iso-propyl protecting groups could be selectively cleaved and the intermediate para-hydroquinone oxidized on air to the desired para-quinone 2 (86% yield). The compound shows some key features (macrolactam ring with the same ringsize, α,β,γ,δ-unsaturated anilide, para-quinone) of geldanamycin.
Chiral building blocks from d-xylose and their application in synthesis of avocadotriol monoacetate
作者:Jian Gao、Zhi-Bin Zhen、Ya-Jun Jian、Yikang Wu
DOI:10.1016/j.tet.2008.07.103
日期:2008.9
Facile routes to several enantiomerically pure flexible chiralbuildingblocks carrying a hidden syn or anti 1,3-diolmotif were developed with the inexpensive and readily available carbohydrate d-xylose as the starting material. Application of the newly developed chiralbuildingblocks in total synthesis is exemplified through a synthesis of (2S,4S)- and (2S,4R)-avocadotriol. Both triols were selectively
以廉价且易于获得的碳水化合物d-木糖为原料,开发了通往带有对映体纯净的柔性手性结构单元的简便途径,这些手性结构单元具有隐藏的合成或反1,3-二醇基序。通过合成(2 S,4 S)-和(2 S,4 R)-鳄梨三醇来举例说明新开发的手性结构单元在总合成中的应用。用诺维信435 /乙酸乙烯酯高产率地将两种三醇选择性地在伯羟基上乙酰化。根据1 H NMR,旋光度和熔点数据的比较,将天然鳄梨三醇1-单乙酸酯定为(2 R,4 R)配置。
Synthesis of Optically Active α-Alkylidene-β-hydroxy-γ-methylenebutyrolactones. Isoobtusilactones and Isomahubalactones (Isomahubanolide and Isomahubenolide)
The title compounds were prepared via stereoselective aldol reaction of α,β-unsaturated carboxylate α-anion equivalent, derived from optically active α-(arylsulfinyl)carboxylate and bromomagnesium diisopropylamide, with propargyl aldehyde as a key step.
High polymer, ferro-electric liquid-crystalline composition containing the high polymer and raw material of the high polymer
申请人:IDEMITSU KOSAN COMPANY LIMITED
公开号:EP0578135A2
公开(公告)日:1994-01-12
This invention provides a high polymer having the following repeating unit (I), a diene compound which is represented by the following formula (II) and is a raw material of the high polymer:
and a ferroelectric liquid-crystalline composition containing the high polymer and a low molecular weight smectic liquid-crystalline compound. The ferroelectric liquid-crystalline composition is easy to orient and exhibits a fast response against applied electric field.
Total synthesis of cis-solamin A was accomplished without using protecting groups starting from (-)-muricatacin in 11 steps with an overall yield of 4.5%. The backbone of cis-solamin A was constructed by olefin cross-metathesis between the tetrahydrofuran moiety and gamma-lactone moiety. An enzymatic kinetic transesterification procedure was successfully applied to the synthesis of an optically pure gamma-lactone moiety. (C) 2007 Elsevier Ltd. All rights reserved.