Reaction of magnesium cyclopropylidene with N-lithio arylamines: a method for generation of α-amino-substituted cyclopropylmagnesiums and a study for their reactivity with electrophiles
摘要:
Magnesium cyclopropylidene was generated from 1-chlorocyclopropyl phenyl sulfoxide with i-PrMgCl in THF at -78 degrees C in high yield by a sulfoxide-magnesium exchange reaction. The generated magnesium cyclopropylidene was found to be reactive with N-lithio arylamines to give alpha-ammo-substituted cyclopropylmagnesiums. The reaction of the a-amino-substituted cyclopropylmagnesiums with several electrophiles was examined and a new method for a synthesis of cyclopropane amino acid derivatives was realized. (c) 2006 Elsevier Ltd. All rights reserved.
Method for producing transition metal compounds and their use for the polymerization of olefins
申请人:——
公开号:US20030191334A1
公开(公告)日:2003-10-09
The invention relates to a method for producing special transition metal compounds, to novel transition metal compounds and to their use for the polymerization of olefins.
这项发明涉及一种生产特殊过渡金属化合物的方法,新型过渡金属化合物以及它们用于烯烃聚合的用途。
A general and enantiodivergent method for the asymmetric synthesis of piperidine alkaloids: concise synthesis of (R)-pipecoline, (S)-coniine and other 2-alkylpiperidines
作者:Juan Etxebarria、Jose L. Vicario、Dolores Badía、Luisa Carrillo
DOI:10.1016/j.tet.2007.08.067
日期:2007.11
A simple and very efficient protocol for the preparation of highly enantioenriched 2-alkylpiperidines has been set up, which allows the preparation of the final heterocycles with any wanted configuration at the stereogenic center starting from the same starting material. The key step of the synthesis relies on a diastereodivergent aza-Michael reaction protocol using the readily available and cheap
Double asymmetric induction as a mechanistic probe: conjugate addition for the asymmetric synthesis of a pseudotripeptide
作者:Stephen G. Davies、Gesine J. Hermann、Miles J. Sweet、Andrew D. Smith
DOI:10.1039/b401293c
日期:——
Double asymmetric induction as a mechanistic probe indicates that, for the conjugateaddition of (R)- and (S)-lithium N-benzyl-N--alpha-methylbenzylamide to (S)-3'-phenylprop-2'-enoyl-4-benzyloxazolidinone, the reactive conformation of the N-acyl oxazolidinone is the anti-s-cis form, facilitating the asymmetricsynthesis of a pseudotripeptide.
Studies of 2,5;6,10;8,10-tri-µ-hydro-nonahydro-nido-nonaborate(1–), [B<sub>9</sub>H<sub>12</sub>]<sup>–</sup>: preparation, crystal and molecular structure, nuclear magnetic resonance spectra, electrochemistry, and reactions
作者:Grant B. Jacobsen、Dominic G. Meina、John H. Morris、Colin Thomson、Steven J. Andrews、David Reed、Alan J. Welch、Donald F. Gaines
DOI:10.1039/dt9850001645
日期:——
Studies of 2,5;6,10;8,10-tri-µ-hydro-nonahydro-nido-nonaborate(1–)[B9H12]– have involved new syntheses, which have led to crystals suitable for the determination of the X-ray crystal and molecular structure, through reactions of B9H13(SMe2) with [OCN]– or other bases. Crystallographic study of [N(PPh3)2][B9H12] reveals the structure of the anion to be that of a nido-nine-vertex cage, based on the parent
Asymmetric synthesis of the marine alkaloid (−)-(S)-nakinadine C
作者:Stephen G. Davies、Paul M. Roberts、Rushabh S. Shah、James E. Thomson
DOI:10.1016/j.tetlet.2013.09.043
日期:2013.11
The first asymmetricsynthesis of the marine alkaloid (−)-(S)-nakinadine C is described. This synthesis employs the conjugate addition of lithium dibenzylamide to an N-α-phenylacryloyl SuperQuat derivative followed by diastereoselective protonation of the intermediate enolate using 2-pyridone as the key step to introduce the stereochemistry. (−)-(S)-Nakinadine C was isolated in 13% yield over 9 steps
描述了海洋生物碱(-)-(S)-那金那丁C的第一个不对称合成。该合成方法是将二苄基酰胺锂共轭添加到N -α-苯基丙烯酰基SuperQuat衍生物中,然后使用2-吡啶酮作为引入立体化学的关键步骤,对中间烯醇化物进行非对映选择性质子化。通过9步从市场上可买到的atropic酸,98:2 dr [(Z : :(E)比率]和> 99%ee的条件下,以13%的产率分离出(-)-(S)-NakinadineC 。