Highly Diastereoselective Synthesis of 2,6-Di[1-(2-alkylaziridin-1-yl)alkyl]pyridines, Useful Ligands in Palladium-Catalyzed Asymmetric Allylic Alkylation
作者:Diego Savoia、Giuseppe Alvaro、Romano Di Fabio、Claudio Fiorelli、Andrea Gualandi、Magda Monari、Fabio Piccinelli
DOI:10.1002/adsc.200606109
日期:2006.9
6-pyridinedicarbaldehyde and (S)-valinol or (S)-phenylglycinol. The new compounds were tested as ligands in palladium-catalyzed allylation of carbanions in different solvents. Almost quantitative yield and up to 99 % enantiomeric excess were obtained in the reactions of the enolates derived from malonate, phenyl- and benzylmalonate dimethyl esters with 1,3-diphenyl-2-propenyl ethyl carbonate.
C 2-对映体纯的2,6-二[1-(1-(叠氮基烷基)烷基]吡啶对映体(DIAZAP)是通过高产率的三步法制备的,从2,6-吡啶二甲醛和(S)-缬氨醇开始或(S)-苯基甘氨醇。在钯催化的不同溶剂中碳负离子的烯丙基化反应中,将这些新化合物作为配体进行了测试。在衍生自丙二酸酯,苯基丙二酸和苄基丙二酸酯二甲基酯的烯酸酯与1,3-二苯基-2-丙烯基碳酸酯的反应中,获得了几乎定量的产率和高达99%的对映体过量。
Optically active borinic esters and ketones
申请人:Aldrich-Boranes, Inc.
公开号:US04868337A1
公开(公告)日:1989-09-19
A process for synthesizing an optically pure ketone comprising the steps of: treating an appropriate optically pure boronic ester with an organolithium compound at -78.degree. C. to obtain the "ate" complex, separating the optically pure borinic ester from the complex and converting said borinic ester into an optically pure ketone represented by the formulae: R*COR.sup.1 and R*COC.tbd.CR.sup.1 wherein R* is a chiral organyl moiety and R.sup.1 is an achiral organyl moeity.
Proton Magnetic Resonance Spectroscopy. Configurational Stability of Neohexyl(3,3-dimethylbutyl) Organometallic Compounds<sup>1</sup>
作者:Michal Witanowski、John D. Roberts
DOI:10.1021/ja00956a023
日期:1966.2
The protonresonancespectra of dilute ether solutions of neohexyl(3,3-dimethylbutyl) organometallic compounds have been investigated as a function of temperature as a means of determining their configurational stabilities. Neohexyllithium, dineohexylmagnesium (free from magnesium chloride), and dineohexylzinc appear to undergo the inversion of configuration at the a-methylene groups at various temperatures
Cerium(III) chloride promoted addition of organometallic reagents to (−)-menthone—preparation of chiral neomenthyl derivatives †Dedicated to Professor Dr. Karl-Heinz Thiele on the occasion of his 70th birthday. †
作者:Stefan Panev、Vladimir Dimitrov
DOI:10.1016/s0957-4166(00)00087-2
日期:2000.4
The activation of (−)-menthone with anhydrous CeCl3 led to high yielding additions of different organometallic reagents. Products of exclusively equatorial-addition of the reagents were obtained; only PhMgBr yielded additionally ca. 5% of the axial-addition product.