Phosphaadamantanes as Ligands for Palladium Catalyzed Cross-Coupling Chemistry: Library Synthesis, Characterization, and Screening in the Suzuki Coupling of Alkyl Halides and Tosylates Containing β-Hydrogens with Boronic Acids and Alkylboranes
作者:Tim Brenstrum、David A. Gerristma、George M. Adjabeng、Christopher S. Frampton、James Britten、Alan J. Robertson、James McNulty、Alfredo Capretta
DOI:10.1021/jo048875+
日期:2004.10.1
allowed for the rapid determination of the most suitable ligand, specifically 1,3,5,7-tetramethyl-6-(2,4-dimethoxyphenyl)-2,4,8-trioxa-6-phosphaadamantane, for facilitating Suzuki-type couplings of alkylhalides or tosylates containing β-hydrogens with either boronic acids or alkylboranes.
iron-catalyzed cross-electrophile coupling of aryl chlorides with unactivated alkylchlorides via an iron/B2pin2 catalytic system has been developed. (Hetero)aryl chlorides undergo this transformation smoothly under mild conditions, furnishing the alkylated products with good efficiency. This protocol features excellent functional group compatibility and gram-scale synthesis, which also enables the late-stage functionalization
Zinc-promoted umpolung thiolation of alkyl electrophiles with masked sulfur transfer reagents in the absence of nickel or copper catalysis is described. This protocol proceeds via a SET process of Zn to electrophilic sulfur reagent followed by insertion of Zn into disulfide and nucleophilic thiolation, providing straightforward access to a wide range of alkyl sulfides with broad substrate scope. A
描述了在没有镍或铜催化的情况下,使用掩蔽硫转移试剂对烷基亲电子试剂进行锌促进的还原硫醇化。该方案通过Zn 与亲电硫试剂的 SET 过程进行,然后将 Zn 插入二硫化物和亲核硫醇化,从而可以直接获得具有广泛底物范围的各种烷基硫醚。合成、分离并通过 NMR、IR 和 X 射线分析充分表征了具有四面体几何形状的中性 TMEDA 连接的四配位硫醇锌。更重要的是,这种活性中间体的化学反应性已经得到研究,能够构建 C-SE、C-Te、Sb-S 和 Bi-S 键,以制备有价值的含硫分子等。