Single-Pot Access to Bisorganoborinates: Applications in Zweifel Olefination
摘要:
Zweifel olefination is a catalyst-free reaction that serves alkene functionalization. While most methods employ commercially available boron pinacol esters, we have assembled a sequence in which the two partners of the formal coupling reaction are installed successively, starting from inexpensive boron alkoxides. The in situ formation of bisorganoborinates was accomplished by consecutive reaction of two different organometallic species. This single-pot procedure represents a great advancement in the generation of organoborinates and their involvement in C-C bond formation.
Ammonium iodide-induced sulfonylation of alkenes with DMSO and water toward the synthesis of vinyl methyl sulfones
作者:Xiaofang Gao、Xiaojun Pan、Jian Gao、Huawen Huang、Gaoqing Yuan、Yingwei Li
DOI:10.1039/c4cc07606k
日期:——
A novel ammonium iodide-induced sulfonylation of alkenes with DMSO and water toward the synthesis of vinyl methylsulfones is described. The process proceeded smoothly under metal-free conditions with high stereoselectivity and good functional group tolerance. The reaction mechanism was revealed to proceed through a domino reaction of oxidation and elimination after the radical addition to alkenes
methodologies and occurs through a trifluoroacyl radical mechanism promoted by a photocatalyst, which triggers a C−O bond fragmentation. Mechanistic studies (kineticisotopeeffects, spectroelectrochemistry, optical spectroscopy, theoretical investigations) highlight the evidence of a fleeting CF3CO radical under photoredox conditions. The trifluoroacyl radical can be stabilized under CO atmosphere, delivering
我们报告了一种温和且操作简单的烯烃三氟酰化策略,该策略利用三氟乙酸酐作为低成本且易于获得的试剂。这种光介导的过程与传统方法有着根本的不同,它通过由光催化剂促进的三氟酰基自由基机制发生,从而触发 CO 键断裂。机理研究(动力学同位素效应、光谱电化学、光谱学、理论研究)突出了转瞬即逝的 CF 3的证据光氧化还原条件下的 CO 自由基。三氟酰基自由基可以在 CO 气氛下稳定,提供具有更高化学效率的三氟乙酰化产物。此外,该方法可以通过简单地改变反应参数变成三氟甲基化协议。除了简单的烯烃外,该方法还允许小分子药物和常见药效团的化学和区域选择性功能化。
Irradiation-Induced Palladium-Catalyzed Decarboxylative Heck Reaction of Aliphatic <i>N</i>-(Acyloxy)phthalimides at Room Temperature
作者:Guang-Zu Wang、Rui Shang、Yao Fu
DOI:10.1021/acs.orglett.8b00023
日期:2018.2.2
It is reported that Pd(PPh3)2Cl2 in combination with 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (Xantphos) under irradiation of blue LEDs efficiently catalyzes a decarboxylative Heck reaction of vinyl arenes and vinyl heteroarenes with aliphatic N-(acyloxy)phthalimides at roomtemperature. A broad scope of secondary, tertiary, and quaternary carboxylates, including α-amino acid derived esters
alkylthiolation of alkenes, initiated by dimethyl(methylthio)sulfonium salts and the subsequent addition of various heteronucleophilies has been well-established. Regarding the use of carbon nucleophiles, however, only carefully designed sp-type carbon sources have been successfully applied. We herein present our findings on the methylthiolation of alkenes with dimethyl(methylthio)sulfonium trifluoromethanesulfonate
Irradiation-Induced Heck Reaction of Unactivated Alkyl Halides at Room Temperature
作者:Guang-Zu Wang、Rui Shang、Wan-Min Cheng、Yao Fu
DOI:10.1021/jacs.7b10009
日期:2017.12.20
eliminable β-hydrogen atoms. Whereas most palladium-catalyzed cross-coupling reactions utilize the ground-state reactivity of palladium complexes under thermal conditions and generally apply a single ligand system, we report that the palladium-catalyzedHeckreaction proceeds smoothly at room temperature with a variety of tertiary, secondary, and primary alkylbromides upon irradiation with blue light-emitting