Han Gi Uk, Baek Yonghyeon, Lee Kyungsup, Shin Seohyun, Chan Noh Hee, Lee Phil Ho
Department of Chemistry, Kangwon National University, Chuncheon 24341, Republic of Korea.
The Korean Academy of Science and Technology, Seongnam 13630, Republic of Korea.
Org Lett. 2021 Jan 15;23(2):416-420. doi: 10.1021/acs.orglett.0c03927. Epub 2020 Dec 30.
Described is the Ir-catalyzed cage B(4)-amidation of -carboranes with dioxazolones by carboxylic acid-assisted B(4)-H bond activation under extremely mild conditions, affording amidated -carboranes and amidated and methoxycarbonylated -carboranes through sequential B(4)-amidation, O-methylation, and B(3)-deboronation in one pot. Carboxylic acid used as a directing group after the cage B(4)-amidation is efficiently trapped by trimethylsilyldiazomethane instead of undergoing decarboxylation. Mechanism studies demonstrated that the O-methylation through trapping of acid occurred first, followed by the B(3)-deboronation.
描述了在极其温和的条件下，通过羧酸辅助的B(4)-H键活化，铱催化的-碳硼烷与二恶唑酮进行笼状B(4)-酰胺化反应，通过一锅法依次进行B(4)-酰胺化、O-甲基化和B(3)-脱硼反应，得到酰胺化的-碳硼烷以及酰胺化和甲氧基羰基化的-碳硼烷。笼状B(4)-酰胺化后用作导向基团的羧酸被三甲基硅基重氮甲烷有效捕获，而不是发生脱羧反应。机理研究表明，首先通过捕获酸发生O-甲基化，然后是B(3)-脱硼反应。
