Para-Selective, Iridium-Catalyzed C-H Borylations of Sulfated Phenols, Benzyl Alcohols, and Anilines Directed by Ion-Pair Electrostatic Interactions
Para-Selective, Iridium-Catalyzed C-H Borylations of Sulfated Phenols, Benzyl Alcohols, and Anilines Directed by Ion-Pair Electrostatic Interactions
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DOI：
10.1021/jacs.9b08464
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发表时间：
2019-10-02
影响因子：
15
通讯作者：
Maleczka, Robert E., Jr.
中科院分区：
文献类型：
--
作者：
Bastidas, Jose R. Montero;Oleskey, Thomas J.;Maleczka, Robert E., Jr.
用联吡啶配位的铱硼基催化剂实现了四烷基硫酸铵和氨基磺酸铵的帕拉对C-H硼基化反应。选择性可以通过四烷基铵阳离子中的烷基的长度和联吡啶配体上的取代基来调节。离子配对，其中阳离子的烷基屏蔽抗衡阴离子中的Meta C-H键，提出占帕拉选择性。4，4 ′-二甲氧基-2，2 ′-联吡啶配体具有上级选择性。
Para C-H borylations (CHB) of tetraalkylammonium sulfates and sulfamates have been achieved using bipyridine-ligated Ir boryl catalysts. Selectivities can be modulated by both the length of the alkyl groups in the tetraalkylammonium cations and the substituents on the bipyridine ligands. Ion pairing, where the alkyl groups of the cation shield the meta C-H bonds in the counter-anions, is proposed to account for para selectivity. The 4,4'-dimethoxy-2,2'-bipyridine ligand gave superior selectivities.