Les acylresidents α-chiraux montrent des preference diastereofaciales exceptionnelles dans des addeds nucleophiles quisont suivies d'une protodesilylation par l'anion F − pour donner des alcools secondaires
A Mechanochemical Zinc-Mediated Barbier-Type Allylation Reaction under Ball-Milling Conditions
作者:JieXiang Yin、Roderick T. Stark、Ian A. Fallis、Duncan L. Browne
DOI:10.1021/acs.joc.9b02876
日期:2020.2.21
A ball-milling-enabled zinc-mediatedBarbier-typeallylation reaction is reported. Notably, running the reaction in this manner renders it effective irrespective of the initial morphology of the zinc metal. The process is operationally simple, does not require inert atmospheres or dry solvents, and is reported over a range of aldehyde and ketone substrates; a gram-scale process is demonstrated.
Ti/Pd Bimetallic Systems for the Efficient Allylation of Carbonyl Compounds and Homocoupling Reactions
作者:Alba Millán、Araceli G. Campaña、Btissam Bazdi、Delia Miguel、Luis Álvarez de Cienfuegos、Antonio M. Echavarren、Juan M. Cuerva
DOI:10.1002/chem.201003315
日期:2011.3.28
The allylation, crotylation and prenylation of aldehydes and ketones with stable and easily handled allylic carbonates is promoted by a Ti/Pd catalytic system. This Ti/Pd bimetallic system is especially convenient for the allylation of ketones, which are infrequent substrates in other related protocols, and can be carried out intramolecularly to yield five‐ and six‐membered cyclic products with good
Ti / Pd催化体系可促进醛和酮与稳定且易于处理的烯丙基碳酸酯的烯丙基化,丁酰化和烯丙基化。这种Ti / Pd双金属体系特别适合于酮的烯丙基化,酮是其他相关规程中不常见的底物,并且可以在分子内进行生产,从而产生具有良好立体选择性的五元和六元环状产物。此外,Ti / Pd介导的还原反应和Würtz型二聚反应可以很容易地从碳酸烯丙酯和羧酸酯中进行。
Bulky Aluminum Lewis Acids as Novel Efficient and Chemoselective Catalysts for the Allylation of Aldehydes
作者:Andreas Marx、Hisashi Yamamoto
DOI:10.1055/s-1999-2667
日期:1999.5
Bulky aluminum Lewis acids such as MAD and MABR are introduced as new efficientcatalysts in substoichiometric amounts for the allylation of aldehydes with allyltributylstannane. In addition, chemoselective allylation of a less hindered or aromatic aldehyde was achieved with catalytic amounts of the carbonyl receptor aluminum tris(2,6-diphenyl-phenoxide) (ATPH).
2-Propenyl tin species, prepared from 3-halopropenes or 2-propenyl mesylate with tin(IV) chloride and tetrabutylammoniumiodide in dichloromethane, causes nucleophilic addition to aldehydes to produce the corresponding homoallylic alcohols.
Ti-Catalyzed Barbier-Type Allylations and Related Reactions
作者:Rosa E. Estévez、José Justicia、Btissam Bazdi、Noelia Fuentes、Miguel Paradas、Duane Choquesillo-Lazarte、Juan M. García-Ruiz、Rafael Robles、Andreas Gansäuer、Juan M. Cuerva、J. Enrique Oltra
DOI:10.1002/chem.200802180
日期:2009.3.9
Versatility of titanium: Titanocene(III) complexes catalyze Barbier‐type allylations, intramolecular crotylations (cyclizations), and prenylations of a wide range of aldehydes and ketones. These reactions take place at RT under mild conditions compatible with many functional groups; provide good yields of open‐chain and cyclic homoallylic alcohols, including heterocyclic derivatives; and can be conducted