我们报告了通过芳基硼亲核试剂与丙二酸衍生物偶联的脱羧羰基α-芳基化。这个过程是通过有氧氧化铜催化与脱羧烯醇化物拦截的结合来实现的,这让人联想到聚酮化合物生物合成中的丙二酰辅酶 A 反应性。该方法能够合成含有与现有α-芳基化反应范式不相容的亲电官能团的乙酸单芳基酯衍生物。该反应的效用在药物中间体合成和后期功能化中得到了证明。
Visible Light-Induced Borylation of C–O, C–N, and C–X Bonds
作者:Shengfei Jin、Hang. T. Dang、Graham C. Haug、Ru He、Viet D. Nguyen、Vu T. Nguyen、Hadi D. Arman、Kirk S. Schanze、Oleg V. Larionov
DOI:10.1021/jacs.9b12519
日期:2020.1.22
photocatalytic borylation method that can effect borylation of a wide range of substrates, including strong C‒O bonds, remains elusive. Herein, we report a general, metal-free visible light-induced photocatalytic borylation platform that enables borylation of electron rich derivatives of phenols and anilines, chloroarenes, as well as other haloarenes. The reac-tion exhibits excellent functional group
硼酸是中心重要的功能基序和合成前体。可见光诱导的硼酸化可以提供结构多样化的硼酸盐,但一种广泛有效的光催化硼酸化方法可以影响包括强 C-O 键在内的多种底物的硼化,仍然难以实现。在此,我们报告了一种通用的、无金属的可见光诱导光催化硼化平台,该平台能够对苯酚和苯胺、氯芳烃以及其他卤代芳烃的富电子衍生物进行硼化。该反应表现出优异的官能团耐受性,正如一系列结构复杂底物的硼化反应所证明的那样。值得注意的是,该反应是由吩噻嗪催化的,这是一种简单的有机光催化剂,MW< 200通过质子耦合电子转移机制介导了以前无法实现的可见光诱导的苯酚衍生物单电子还原,还原电位为~-3 V vs SCE。机理研究指出了光催化剂-碱相互作用的关键作用。
Fast Enantio‐ and Chemoselective Arylation of Ketones with Organoboronic Esters Enabled by Nickel/N‐Heterocyclic Carbene Catalysis
作者:Yuan Cai、Lin‐Xin Ruan、Abdul Rahman、Shi‐Liang Shi
DOI:10.1002/anie.202015021
日期:2021.3
tolerates aryl chlorides, fluorides, ethers, esters, amides, nitriles, and alkyl chlorides. The reaction is applied to late‐stage modifications of various densely functionalized medicinally relevant molecules. Preliminary mechanistic studies suggest that a rare enantioselective η2‐coordinating activation of ketone carbonyls is involved. This cross‐coupling‐like mechanism is expected to enable other challenging
Copper-Catalyzed Cross-Coupling Reaction of Organoboron Compounds with Primary Alkyl Halides and Pseudohalides
作者:Chu-Ting Yang、Zhen-Qi Zhang、Yu-Chen Liu、Lei Liu
DOI:10.1002/anie.201008007
日期:2011.4.18
Non‐activated alkylelectrophiles, including alkyl iodides, bromides, tosylates, mesylates, and even chlorides, underwent copper‐catalyzedcross‐coupling with aryl boron compounds and alkyl 9‐BBN reagents (see scheme; 9‐BBN=9‐borabicyclo[3.3.1]nonane). The reactions proceed with practically useful reactivities and thus complement palladium‐ and nickel‐catalyzed Suzuki–Miyaura coupling reactions of alkyl halides
A new method has been developed for the rhodium-catalyzedcross-coupling of aryl carbamates with organoboron reagents. The use of an NHC ligand bearing a 2-adamantyl group, i.e., I(2-Ad), is essential to the success of the reaction. The reaction involves the rhodium-mediated activation of the relatively inert C(aryl)-O bond of aryl carbamates.
of aryl cyanides with diboron in the presence of a rhodium/Xantphos catalyst and DABCO affords arylboronic esters via carbon-cyano bond cleavage. This unprecedented mode of reactivity for a borylrhodium species allows the regioselective introduction of a boryl group in a late stage of synthesis.