本文报道的是铜催化的S N 2'选择性烯丙基取代反应,该反应使用易于获得的烯丙基氯化物和1,1-二硼烷基烷烃,该反应随着1,1-二硼烷基烷烃的化学选择性C-B键活化而进行。在催化量的[Cu(IMes)Cl] [IMes = 1,3-双(2,4,6-三甲基苯基)咪唑-2-亚烷基]和LiO t Bu为碱的情况下,一系列伯仲烯丙基氯化物经过S N 2'-选择性烯丙基取代反应,生成支链烷基硼酸酯。还介绍了所得烷基硼酸酯的合成用途。
Expedient access to branched allylic silanes by copper-catalysed allylic substitution of linear allylic halides
作者:Devendra J. Vyas、Martin Oestreich
DOI:10.1039/b920793g
日期:——
An unprecedented copper-catalysed allylic transposition enables the regioselectivesynthesis of branched allylic silanes from linear allylichalides through direct C-Si bond formation.
imidazolium salts, γ-substituted allyl chlorides reacted with alkyl Grignard reagents to undergo substitution reactions in an SN2′-selective fashion, where the magnesium ate complexes [(N-heterocyclic carbene-MgR3)−(MgX)+] of imidazol-2-ylidenes or imidazol-4-ylidenes, generated in situ, were postulated as the active species. It was observed that the reactions with imidazol-4-ylidene catalysts were faster
在催化量的1,2-二取代或1,2,3-三取代的咪唑鎓盐的存在下,γ-取代的烯丙基氯与烷基格氏试剂反应,以S N 2'-选择性方式进行取代反应,其中假定将原位生成的咪唑-2-亚胺或咪唑-4-亚胺的镁盐配合物[(N-杂环卡宾-MgR 3)-(MgX)+ ]作为活性物质。观察到与咪唑-4-亚烷基催化剂的反应比与咪唑-2-亚烷基催化剂的反应更快。初步研究了使用手性咪唑盐的对映选择性催化。
Enantioselective Synthesis of Tertiary and Quaternary Stereogenic Centers: Copper/Phosphoramidite-Catalyzed Allylic Alkylation with Organolithium Reagents
作者:Martín Fañanás-Mastral、Manuel Pérez、Pieter H. Bos、Alena Rudolph、Syuzanna R. Harutyunyan、Ben L. Feringa
DOI:10.1002/anie.201107840
日期:2012.2.20
An efficient and highly enantioselectivecopper‐catalyzed allylic alkylation of disubstituted allyl halides with primary and secondary organolithium reagents using phosphoramidite ligands is reported. The use of trisubstituted allyl bromides allows, for the first time, the enantioselective synthesis of all‐carbon quaternary stereogenic centers with these reactive organometallic reagents.
作者:Damien Polet、Xavier Rathgeb、Caroline A. Falciola、Jean-Baptiste Langlois、Samir El Hajjaji、Alexandre Alexakis
DOI:10.1002/chem.200801879
日期:2009.1.19
We describe herein the development of the first iridium‐catalyzed allylic substitution using arylzinc nucleophiles. High enantioselectivities were obtained from the reactions, which used commercially available Grignardreagents as the starting materials. This methodology was also shown to be compatible with halogen/metal exchange reactions. Its synthetic potential is demonstrated by its application
asymmetric auto‐tandem reaction catalyzed by a planar‐chiral cyclopentadienyl–ruthenium complex is described. The reaction of allylic chloride with α‐haloamides provides synthetically useful, diastereomerically and enantiomerically enriched γ‐lactams with multiple stereogenic centers through one‐pot sequential allylic amidation/atom‐transferradicalcyclization. PG=protecting group.