Herein, we report the first example of group transfer radical addition of O-vinylhydroxylamine derivatives onto unactivatedalkenes. By utilizing O-vinylhydroxylamine derivatives as both the N- and C-donors, this reaction enables intermolecular carboamination of unactivatedalkenes in an atom economical fashion. As the process is initiated through N-radical addition followed by C-transfer, linear carboamination
在此,我们报告了第一个将 O-乙烯基羟胺衍生物基团转移自由基加成到未活化烯烃上的例子。通过使用 O-乙烯基羟胺衍生物作为 N 和 C 供体,该反应能够以原子经济的方式对未活化的烯烃进行分子间碳胺化。由于该过程是通过 N-自由基加成和 C-转移引发的,因此提供了线性碳胺化产物。这与烯烃的经典自由基碳官能化不同,后者通常有利于支链产物,因为它是由 C-自由基加成引发的。
Photoinduced Copper‐Catalyzed Asymmetric Decarboxylative Alkynylation with Terminal Alkynes
作者:Hai‐Dong Xia、Zhong‐Liang Li、Qiang‐Shuai Gu、Xiao‐Yang Dong、Jia‐Heng Fang、Xuan‐Yi Du、Li‐Lei Wang、Xin‐Yuan Liu
DOI:10.1002/anie.202006317
日期:2020.9.21
photoinduced copper‐catalyzed asymmetric radical decarboxylative alkynylation of bench‐stable N‐hydroxyphthalimide(NHP)‐type esters of racemic alkyl carboxylic acids with terminal alkynes, which provides a flexible platform for the construction of chiral C(sp3)−C(sp) bonds. Critical to the success of this process are not only the use of the copper catalyst as a dual photo‐ and cross‐coupling catalyst but
Kinetics of Self-Decomposition and Hydrogen Atom Transfer Reactions of Substituted Phthalimide <i>N</i>-Oxyl Radicals in Acetic Acid
作者:Yang Cai、Nobuyoshi Koshino、Basudeb Saha、James H. Espenson
DOI:10.1021/jo048418t
日期:2005.1.1
reactions of phthalimide N-oxyl radicals (PINO•) and N-hydroxyphthalimide (NHPI) derivatives. The first is the self-decomposition of PINO• which was found to follow second-order kinetics. In the self-decomposition of 4-methyl-N-hydroxyphthalimide (4-Me-NHPI), H-atom abstraction competes with self-decomposition in the presence of excess 4-Me-NHPI. The second set of reactions studied is hydrogen atom transfer
已获得邻苯二甲酰亚胺N-氧基自由基(PINO •)和N-羟基邻苯二甲酰亚胺(NHPI)衍生物的三种不同反应类型的动力学数据。第一个是PINO •的自分解,被发现遵循二级动力学。在4-甲基-N-羟基邻苯二甲酰亚胺(4-Me-NHPI)的自分解中,在过量的4-Me-NHPI存在下,H原子的提取与自分解竞争。研究的第二组反应是氢原子从NHPI转移到PINO •的过程,例如PINO • + 4-Me-NHPI PI NHPI + 4-Me-PINO •。实质KIE,k H / k D对于正向和反向反应,= 11均支持H原子转移而不是逐步电子质子转移的分配。这些数据与氢原子转移的马库斯交叉关系相关,并且在实验和计算的速率常数之间获得了良好的一致性。研究的第三个反应是PINO •从对二甲苯和甲苯中提取氢。•随着PINO •上的环取代基带给电子更多,反应通常会变慢。通过Hammett方程分析,PINO •与对二甲苯和甲苯的反应分别为ρ=
Nickel-Catalyzed C(sp<sup>3</sup>)–C(sp<sup>3</sup>) Cross-Electrophile Coupling of In Situ Generated NHP Esters with Unactivated Alkyl Bromides
作者:Kai Kang、Daniel J. Weix
DOI:10.1021/acs.orglett.2c00805
日期:2022.4.22
The formation of C(sp3)–C(sp3) bonds by cross-coupling remains a challenge in synthesis. Here, we demonstrate a two-step, one-pot protocol for the in situ generation of N-hydroxyphthalimide esters and their nickel-catalyzed cross-electrophile coupling with unactivated alkyl bromides for the construction of 1°/1 ° C(sp3)–C(sp3) bonds. The conditions tolerate an array of functional groups, and mechanistic
Rapid and Modular Access to Quaternary Carbons from Tertiary Alcohols via Bimolecular Homolytic Substitution
作者:Colin A. Gould、Andria L. Pace、David. W. C. MacMillan
DOI:10.1021/jacs.3c05405
日期:2023.8.2
however, synthetic methods for the construction of this motif remain underdeveloped. Here, we report the synthesis of quaternary carbons from tertiary alcohols, a class of structurally diverse, bench-stable feedstocks, via the merger of photoredox catalysis and iron-mediated SH2 bond formation. This alcohol–bromide cross-coupling is enabled by a novel halogen-atom transfer (XAT) reagent, which is the first
季碳普遍存在于生物活性分子中。然而,构建该基序的合成方法仍然不发达。在这里,我们报道了通过光氧化还原催化和铁介导的 S H 2 键形成的结合,从叔醇(一类结构多样、实验室稳定的原料)合成季碳。这种醇-溴化物交叉偶联是通过一种新型卤素原子转移 (XAT) 试剂实现的,这是第一个被报道的还原活化 XAT 试剂。通过这种温和实用的方案可以获得多种空间拥挤的四级产物,包括源自三级片段的烷基化和苄基化的产物。我们通过肝受体激动剂的快速合成以及通过酮和酯向四元产物的两步转化进一步证明了该方法的合成效用,这使得能够对四元中心上四个取代基中的最多三个进行模块化控制。