Li Hui, Yatabe Takafumi, Takayama Satoshi, Yamaguchi Kazuya
Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
JACS Au. 2023 Apr 13;3(5):1376-1384. doi: 10.1021/jacsau.3c00049. eCollection 2023 May 22.
Although catalytic dehydrogenative aromatization from cyclohexanones and NH is an attractive synthetic method for primary anilines, using a hydrogen acceptor was indispensable to achieve satisfactory levels of selectivity in liquid-phase organic synthetic systems without photoirradiation. In this study, we developed a highly selective synthesis of primary anilines from cyclohexanones and NH via efficient acceptorless dehydrogenative aromatization heterogeneously catalyzed by an Mg(OH)-supported Pd nanoparticle catalyst in which Mg(OH) species are also deposited on the Pd surface. The basic sites of the Mg(OH) support effectively accelerate the acceptorless dehydrogenative aromatization via concerted catalysis, suppressing the formation of secondary amine byproducts. In addition, the deposition of Mg(OH) species inhibits the adsorption of cyclohexanones on the Pd nanoparticles to suppress phenol formation, achieving the desired primary anilines with high selectivity.
尽管环己酮与氨之间的催化脱氢芳构化反应是一种颇具吸引力的伯苯胺合成方法，但在无光照射的液相有机合成体系中，使用氢受体对于实现令人满意的选择性水平而言是必不可少的。在本研究中，我们通过由负载在Mg(OH)上的钯纳米颗粒催化剂非均相催化的高效无受体脱氢芳构化反应，开发了一种从环己酮和氨中高选择性合成伯苯胺的方法，其中Mg(OH)物种也沉积在钯表面。Mg(OH)载体的碱性位点通过协同催化有效地加速了无受体脱氢芳构化反应，抑制了仲胺副产物的形成。此外，Mg(OH)物种的沉积抑制了环己酮在钯纳米颗粒上的吸附，从而抑制了苯酚的形成，以高选择性得到了所需的伯苯胺。
