Some new C2-symmetric bicyclo[2.2.1]heptadiene ligands: synthesis and catalytic activity in rhodium(I)-catalyzed asymmetric 1,4- and 1,2-additions
作者:Timothy Noël、Koen Vandyck、Johan Van der Eycken
DOI:10.1016/j.tet.2007.10.034
日期:2007.12
C2-Symmetric bicyclo[2.2.1]hepta-2,5-dienes with various substituents (R=Bn, i-Bu, c-Hex, allyl) are prepared starting from the corresponding enantiomerically pure bis-triflate (R=OTf). These chiral ligands are tested and compared in rhodium(I)-catalyzed 1,4- and 1,2-addition of phenylboronic acid to cyclic enones and aryl aldehydes, respectively. Some interesting reactivity and selectivity effects
Enantioselective synthesis of the tricyclic furan moiety of azadirachtin, a potent insect antifeedant
作者:Hidenori Watanabe、Takeru Watanabe、Kenji Mori
DOI:10.1016/0040-4020(96)00856-3
日期:1996.10
A synthesis of the enantiomerically pure right-hand part (2) of an insectantifeedant, azadirachtin, is described. Reduction with baker's yeast was demonstrated to be efficient for kinetic resolution of racemic diketone (4) to give 3 of ∼75% e.e., from which was derived 2 in 11 steps.
Preparation of<i>C</i><sub>3</sub>-Symmetric Homochiral<i>syn</i>-Trisnorbornabenzenes through Regioselective Cyclotrimerization of Enantiopure Iodonorbornenes
作者:A. F. G. Masud Reza、Shuhei Higashibayashi、Hidehiro Sakurai
DOI:10.1002/asia.200900132
日期:2009.8.3
mixtures. The efficient preparation of (−)‐syn‐1 was established in short steps, including the newly developed cyclotrimerization reaction. The thus‐prepared homochiral (−)‐syn‐1 can serve as a keyintermediate for the synthesis of C3‐symmetric homochiral cup‐shaped molecules with a helical arrangement of substituents. Introduction of several types of substituents was well demonstrated through palladium‐catalyzed
通过钯纳米团簇催化对映纯的碘化冰片的新的区域选择性环三聚,合成了具有刚性杯形结构的C 3-对称同手性(-)-顺式-trisoxonorborna苯1。环三聚的产率取决于钯簇的稳定性,其由反应混合物的外观和TEM图像确定。包括新开发的环三聚反应在内的短步伐就建立了(-)- syn - 1的高效制备方法。如此制备的同手性(-)- syn - 1可以用作合成C 3的关键中间体具有螺旋形取代基的对称对称手性杯状分子。通过钯催化的与(-)- syn - 1的相应磷酸酯和三氟甲磺酸酯的偶合钯偶联反应已很好地证明了几种取代基的引入。
Enantioselective Synthesis of DIANANE, a Novel <i>C</i><sub>2</sub>-Symmetric Chiral Diamine for Asymmetric Catalysis
作者:Albrecht Berkessel、Michael Schröder、Christoph A. Sklorz、Stefania Tabanella、Nadine Vogl、Johann Lex、Jörg M. Neudörfl
DOI:10.1021/jo035841d
日期:2004.4.1
the use of hydrogen peroxide in the form of its urea clathrate instead of aqueous solution proved beneficial. By the above sequence, enantiomerically pure (ee ≥99%) DIANANE was obtained from norbornadiene in 40−50% overall yield. The relative and absolute configuration of DIANANE was confirmed by X-ray crystallography of the DIANANE bis-tosylamide, and of its bis-camphorsulfonamide. Furthermore, the synthesis
Stochastic Bullvalene Architecture Modulates Structural Rigidity in π‐Rich Macromolecules
作者:Meredith Nancy Pomfret、Peiguan Brian Sun、Zheng Huang、Anna Carrie Freund、Toshikazu Miyoshi、Matthew Ross Golder
DOI:10.1002/anie.202301695
日期:——
Bullvalene, a shape-shifting molecular cage, is incorporated into a pi-rich polymer backbone to modulate chain architecture. Stochastic bullvalene isomers within the backbone lead to a kinked chain architecture and decreased thermal transitions that are tunable based on percent bullvalene incorporation.
Bullvalene 是一种变形分子笼,被掺入富含 pi 的聚合物主链中以调节链结构。主链内的随机 bullvalene 异构体导致扭结链结构和减少的热转变,这是基于 bullvalene 掺入百分比可调的。