提出了一种用于羰基化合物烯丙基化的温和方法。这种方法允许以烯丙基碳酸酯作为原亲核试剂对范围广泛的羰基化合物进行烯丙基化。值得注意的是,在其他相关协议中不常见的底物酮是这些反应条件下的合适底物。此外,反应在室温下进行,使用催化量的 Ni 和 Ti 催化剂。该策略的成功基于后期过渡金属(镍)和自由基试剂(钛)之间的完美匹配。使用 Ni 代替 Pd 扩大了这种转变的范围并使这种方法更加经济。
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。
CpTiCl<sub>2</sub>
, an Improved Titanocene(III) Catalyst in Organic Synthesis
作者:Esther Roldan-Molina、Natalia M. Padial、Luis Lezama、J. Enrique Oltra
DOI:10.1002/ejoc.201801120
日期:2018.11.25
CpTiCl2, an improved titanocene(III) single‐electron transfer catalyst, under mild conditions provides excellent yields of homoallylic and homopropargylic alcohols in Barbier‐type allylation and propargylation reactions. Moreover, in the presence of a BOX ligand, it was capable of catalyzingenantioselective intramolecular allylations and propargylations (cyclizations) of ketones.
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
An electrochemical method to prepare solutions of samarium diiodide in THF is reported. The simple electrolysis of a samarium rod provides a rapid and straightforward in situ synthesis of SmI2. The electrogenerated complex catalyzes various CC bond formations. The reagent is produced continuously (see scheme) and leads to efficient organic electrosynthesis with significantly smaller amounts of solvent