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。
A Straightforward Approach towards Functionalized Amino Acids and Pipecolinic Acids via Ruthenium-Catalyzed Allylic Alkylation
作者:Uli Kazmaier、Phil Servatius
DOI:10.1055/s-0034-1378720
日期:——
Chelated amino acid ester enolates react with cis-butene diol substrates via Ru-catalyzed allylic alkylations to functionalized amino acids. The use of [(p-cymene)RuCl2]2 as catalyst allows the introduction of Z-configured allylic alcohols in the side chain of the amino acid. They facilitate access to pipecolinic acid and baikiaine derivatives.
copper-catalyzed highly enantioselective umpolung allylic acylation reaction with acylsilanes as acyl anion equivalents. Triplet-quenching experiments and DFT calculations supported our reaction design, which is based on copper-to-acyl metal-to-ligand charge transfer (MLCT) photoexcitation that generates a charge-separated triplet state as a highly reactive intermediate. According to the calculations
Copper‐Catalyzed B(dan)‐Installing Allylic Borylation of Allylic Phosphates
作者:Hiroto Yoshida、Yuya Murashige、Itaru Osaka
DOI:10.1002/adsc.201900342
日期:2019.5.14
γ‐Selective B(dan)‐installing allylic borylation was found to proceed efficaciously by the reaction of an unsymmetrical diboron, (pin)B−B(dan), with allylic phosphates under copper catalysis. The resulting allyl−B(dan) was convertible into 1,3‐, 1,2‐, or 1,1‐diborylalkanes with different boron‐Lewis acidity by B(pin)‐installing hydroboration, and its C(sp3)−B(dan) bond turned out to be preferentially