Copper(I)–Thiazol-2-ylidenes: Highly Reactive N-Heterocyclic Carbenes for the Hydroboration of Terminal and Internal Alkynes. Ligand Development, Synthetic Utility, and Mechanistic Studies
Copper(I)–Thiazol-2-ylidenes: Highly Reactive N-Heterocyclic Carbenes for the Hydroboration of Terminal and Internal Alkynes. Ligand Development, Synthetic Utility, and Mechanistic Studies
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Copper(I)-Thiazol-2-ylidenes：用于末端和内部炔烃的硼氢化反应的高反应性 N-杂环卡宾。
DOI：
10.1021/acscatal.2c04668
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发表时间：
2022
期刊：
影响因子：
12.9
通讯作者：
Szostak, Michal
中科院分区：
文献类型：
--
作者：
Zhang, Jin;Li, Xue;Li, Tao;Zhang, Gaopeng;Wan, Kerou;Ma, Yangmin;Fang, Ran;Szostak, Roman;Szostak, Michal
在过去的15年中，利用硼基铜的铜催化硼化转化已被确立为有机合成和催化中的强大活化模式，使得各种π-体系的直接转化成为可能。虽然许多这些转换使用NHC（N-杂环卡宾）配体，这些研究已几乎完全限于咪唑-2-亚基的衍生物。然而，N-芳基-咪唑-2-亚基，如IPr（IPr = 1，3-双（2，6-二异丙基苯基）咪唑-2-亚基）的分子性质受限于（1）高度的杂原子稳定性和（2）氮原子的对称取代。本文中，我们报道了对Cu（I）-噻唑-2-亚基，咪唑-2-亚基的噻唑类似物的研究，其（1）具有独特的半伞形配位配体和（2）通过减少来自硫的π-供给而表现出辅助配体的较低杂原子稳定性。本文报道了一类稳定的Cu（I）-噻唑-2-亚基化合物的合成、晶体学性质及其在炔硼氢化反应中的应用，其中噻唑-2-亚基化合物的空间位阻结合形成单体[Cu（NHC）X]或桥卤二聚体[Cu（NHC）（μ-X）]2，通过内炔的β-硼氢化反应得到三取代的乙烯基硼酸酯，通过末端炔的β-硼氢化反应得到末端乙烯基硼酸酯。介绍了该催化剂在后期改性中的应用，并对催化剂的结构和活化机理进行了详细的研究。最重要的是，Cu（I）-噻唑-2-亚基在炔的硼氢化中显示出比经典咪唑-2-亚基高得多的β-选择性，从而在环境条件下以优异的产率提供乙烯基硼。噻唑-2-亚基的独特的“半伞”形状逆转了在末端炔的硼氢化中用咪唑-2-亚基观察到的α/β区域选择性。动力学研究表明，Cu（I）-噻唑-2-亚基取代咪唑-2-亚基。考虑到π-体系的硼基化转化的重要用途，我们预期Cu（I）-噻唑-2-亚基将促进硼基铜在有机合成和催化中的合成转化。
In the last 15 years, copper-catalyzed borylative transformations utilizing boryl–copper have been established as a powerful activation mode in organic synthesis and catalysis, enabling direct transformations of various π-systems. Although many of these transformations use NHC (N-heterocyclic carbene) ligands, these studies have been almost exclusively limited to the derivatives of imidazol-2-ylidenes. However, the molecular properties ofN-aryl-imidazol-2-ylidenes, such as IPr (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene), are limited by (1) the high degree of heteroatom stabilization and (2) symmetrical substitution of the nitrogen atoms. Herein, we report a study on Cu(I)–thiazol-2-ylidenes, thiazole analogues of imidazol-2-ylidenes, which (1) feature a distinct half-umbrella shape of the coordinating ligand and (2) exhibit lower heteroatom stabilization of the ancillary ligand through reduced π-donation from sulfur. We present the development of a family of stable Cu(I)–thiazol-2-ylidenes, where the combined sterics of thiazol-2-ylidenes lead to monomers [Cu(NHC)X] or bridged-halo dimers [Cu(NHC) (μ-X)]2, their crystallographic characteristics, and application to the hydroboration of alkynes to afford trisubstituted vinylboronates by β-hydroboration of internal alkynes or terminal vinylboronates by β-hydroboration of terminal alkynes. Application to the late-stage modification and detailed mechanistic studies on the catalyst structure and activation are presented. Most crucially, Cu(I)–thiazol-2-ylidenes show a much higher β-selectivity in the hydroboration of alkynes than that of classical imidazol-2-ylidenes, affording vinylborons in excellent yields at ambient conditions. The unique “half-umbrella” shape of thiazol-2-ylidenes reverses the α/β regioselectivity observed with imidazol-2-ylidenes in the hydroboration of terminal alkynes. Kinetic studies demonstrate that Cu(I)–thiazol-2-ylidenes supersede imidazol-2-ylidenes. Considering the significant utility of borylative transformations of π-systems, we anticipate that Cu(I)–thiazol-2-ylidenes will advance the synthetic transformations of boryl–copper in organic synthesis and catalysis.
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影响因子：
15
作者：
Lee Y;Hoveyda AH
通讯作者：
Hoveyda AH
影响因子：
5.8
作者：
Zhou, Tongliang;Ma, Siyue;Szostak, Michal
通讯作者：
Szostak, Michal
影响因子：
5.9
作者：
Zhang, Jin;Li, Tao;Li, Xiangyang;Lv, Anqi;Li, Xue;Wang, Zheng;Wang, Ruihong;Ma, Yangmin;Fang, Ran;Szostak, Roman;Szostak, Michal
通讯作者：
Szostak, Michal
自由基介导的卡宾催化
DOI：
--
发表时间：
2021
期刊：
影响因子：
--
作者：
Otsuki Joe;Okumura Takumi;Sugawa Kosuke;Kawano Shin‐ichiro;Tanaka Kentaro;Hirao Takehiro;Haino Takeharu;Lee Yu Jin;Kang Seongsoo;Kim Dongho;大宮寛久;片島拓弥;Hirohisa Ohmiya
通讯作者：
Hirohisa Ohmiya
铱(I) 苯并噻唑啉-2-亚基配合物
影响因子：
2.8
作者：
H. Huynh;Nicole Meier;T. Pape;F. Hahn
通讯作者：
F. Hahn