Pd-Catalyzed Suzuki-Miyaura Cross-Coupling of Pentafluorophenyl Esters
Pd-Catalyzed Suzuki-Miyaura Cross-Coupling of Pentafluorophenyl Esters
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DOI：
10.3390/molecules23123134
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发表时间：
2018-12-01
期刊：
影响因子：
4.6
通讯作者：
Szostak, Michal
中科院分区：
文献类型：
--
作者：
Buchspies, Jonathan;Pyle, Daniel J.;Szostak, Michal
尽管钯催化的芳基酯的 Suzuki-Miyaura 交叉偶联受到了广泛关注，但缺乏利用廉价且易于获得的 Pd-Phosphane 催化剂且能够以高交叉偶联选择性常规进行的方法。在此，我们报告了第一个通过选择性 C-O 酰基裂解进行五氟苯酯（五氟苯基 = pfp）交叉偶联的通用方法。使用 Pd(0)/膦催化剂系统，反应可以有效进行。五氟苯酯的独特特性体现在与酚酯相比的完全选择性交叉偶联。该报告通过酰基金属中间体将五氟苯酯确定为新型、高反应性、实验室稳定、经济、酯基、亲电酰化试剂，具有广泛的合成意义。机理研究有力地支持了 C(O)-X (X = N, O) 活化酰基亲电子试剂的统一反应性尺度。 pfp 酯的反应性可能与 C（酰基）-O 键周围异构化的障碍相关。
Although the palladium-catalyzed Suzuki-Miyaura cross-coupling of aryl esters has received significant attention, there is a lack of methods that utilize cheap and readily accessible Pd-phosphane catalysts, and can be routinely carried out with high cross-coupling selectivity. Herein, we report the first general method for the cross-coupling of pentafluorophenyl esters (pentafluorophenyl = pfp) by selective C-O acyl cleavage. The reaction proceeds efficiently using Pd(0)/phosphane catalyst systems. The unique characteristics of pentafluorophenyl esters are reflected in the fully selective cross-coupling vs. phenolic esters. Of broad synthetic interest, this report establishes pentafluorophenyl esters as new, highly reactive, bench-stable, economical, ester-based, electrophilic acylative reagents via acyl-metal intermediates. Mechanistic studies strongly support a unified reactivity scale of acyl electrophiles by C(O)-X (X = N, O) activation. The reactivity of pfp esters can be correlated with barriers to isomerization around the C(acyl)-O bond.