Selective Terminal Heck Arylation of Vinyl Ethers with Aryl Chlorides: A Combined Experimental−Computational Approach Including Synthesis of Betaxolol
作者:Gopal K. Datta、Henrik von Schenck、Anders Hallberg、Mats Larhed
DOI:10.1021/jo0602367
日期:2006.5.1
medium. The selectivity for linear β-product in PEG-200 is slightly higher than in aqueous DMF. DFT calculations support a ligand-driven selectivity rationale, where the electronic and steric influence of bulky P(t-Bu)3 ligand provides improved β-selectivity in the essential insertion step also with electron-rich aryl chlorides. A tentative computational rationalization of the improved selectivity in non-methylated
反应条件对于具有高的区域选择性非环状乙烯基醚类的钯催化的终端(β-)芳基化使用廉价的芳基氯作为原料,和P(已开发吨-Bu)3释放preligand [(吨-Bu 3)PH] BF 4作为关键添加剂。这种快速而直接的方案利用了非惰性条件和受控的微波加热,以最大程度地减少了处理和加工时间,并使用了DMF水溶液或环保型PEG-200作为反应介质。PEG-200中线性β产物的选择性略高于水性DMF。DFT计算支持配体驱动的选择性原理,其中大体积P(t-Bu)3配体在必要的插入步骤中也利用富电子的芳基氯化物提供了改进的β-选择性。讨论了在非甲基化PEG中提高选择性的初步计算合理性。最后,该合成方法被用于从对硝基苯氯(一种合成β-肾上腺素阻断剂倍他洛尔的关键中间体)中有效地获得直链对-[2-(环丙基甲氧基)乙基]苯酚。