有机卤化物的催化羰基化是化学合成中重要的 CC 键形成。未活化烷基卤化物的羰基化仍然是一个挑战,目前需要在苛刻条件和高压 CO 下使用烷基碘。在此我们报告了钯催化的仲烷基溴烷氧基羰基化,在温和条件下在低压 (2 atm CO) 下进行. 初步机理研究与混合有机金属-自由基过程一致。这些反应有效地将未活化烷基溴的酯传递到各种底物上,并代表了烷基溴与一氧化碳的第一次催化羰基化。
<i>sp</i><sup>3</sup> C–H Arylation and Alkylation Enabled by the Synergy of Triplet Excited Ketones and Nickel Catalysts
作者:Yangyang Shen、Yiting Gu、Ruben Martin
DOI:10.1021/jacs.8b07405
日期:2018.9.26
polypyridyl complexes. Additionally, such a platform provides a new strategy for streamlining the synthesis of complex molecules with high levels of predictable site-selectivity and preparative utility. Mechanistic experiments suggest that sp3 C-H abstraction occurs via HAT from the ketone triplet excited state. We believe this study will contribute to a more systematic utilization of triplet excited ketones
作者:Gang-Wei Wang、Matthew Wheatley、Marco Simonetti、Diego M. Cannas、Igor Larrosa
DOI:10.1016/j.chempr.2020.04.006
日期:2020.6
meta-selective sp2 C–H alkylation with secondary alkylhalides is well established, ortho selectivity has never been achieved. We demonstrate that the use of a cyclometalated Ru-complex, RuBnN, as the catalyst results in a complete switch of the inherent meta-selectivity to ortho selectivity in the Ru-catalyzed sp2 C–H alkylation reaction with unactivated secondary alkylhalides. The high catalytic activity
Reductive coupling of benzyl oxalates with highly functionalized alkyl bromides by nickel catalysis
作者:Xiao-Biao Yan、Chun-Ling Li、Wen-Jie Jin、Peng Guo、Xing-Zhong Shu
DOI:10.1039/c8sc00609a
日期:——
Coupling reactions involving non-sulfonated C–O electrophiles provide a promising method for forming C–C bonds, but the incorporation of functionalized or secondary alkyl groups remains a challenge due to the requirement for well-defined alkylmetal species. In this study, we report a reductive nickel-catalyzed cross-coupling of benzyl oxalates with alkyl bromides, using oxalate as a new leaving group
Several enantiopure spiroisoxazoline amides were prepared from tert-butylester 22, which is obtained via an enantiotopic groups differentiating high pressure Diels–Alder cycloaddition. Treatment of these amides with an isoxazoline-splitting enzyme, which is involved in an injury induced defense reaction of the sponge Aplysina cauliformis, proves the bromoatoms in the cyclohexenone moiety to be important
Palladium-Catalyzed Alkoxycarbonylation of Unactivated Secondary Alkyl Bromides at Low Pressure
作者:Brendon T. Sargent、Erik J. Alexanian
DOI:10.1021/jacs.6b04610
日期:2016.6.22
Catalytic carbonylations of organohalides are important C-C bond formations in chemical synthesis. Carbonylations of unactivated alkyl halides remain a challenge and currently require the use of alkyl iodides under harsh conditions and highpressures of CO. Herein we report a palladium-catalyzed alkoxycarbonylation of secondary alkyl bromides that proceeds at low pressure (2 atm CO) under mild conditions
有机卤化物的催化羰基化是化学合成中重要的 CC 键形成。未活化烷基卤化物的羰基化仍然是一个挑战,目前需要在苛刻条件和高压 CO 下使用烷基碘。在此我们报告了钯催化的仲烷基溴烷氧基羰基化,在温和条件下在低压 (2 atm CO) 下进行. 初步机理研究与混合有机金属-自由基过程一致。这些反应有效地将未活化烷基溴的酯传递到各种底物上,并代表了烷基溴与一氧化碳的第一次催化羰基化。