A General Strategy for Aliphatic C–H Functionalization Enabled by Organic Photoredox Catalysis
摘要:
Synthetic transformations that functionalize unactivated aliphatic C-H bonds in an intermolecular fashion offer unique strategies for the synthesis and late stage derivatization of complex molecules. Herein we report a general approach to the intermolecular functionalization of aliphatic C-H bonds using an acridinium photoredox catalyst and phosphate salt under blue LED irradiation. This strategy encompasses a range of valuable C-H transformations, including the direct conversions of a C-H bond to C-N, C-F, C-Br, C-Cl, C-S, and C-C bonds, in all cases using the alkane substrate as the limiting reagent. Detailed mechanistic studies are consistent with the intermediacy of a putative oxygen-centered radical as the hydrogen atom-abstracting species in these processes.
Schmidt reaction by sulfonium ions is described. General primary, secondary, and tertiary alkyl azides were converted to the corresponding carbonyl or imine compounds without any trace of the activators. This bond scission reaction through 1,2-migration of C–H and C–C bonds was accessible to the one-pot substitution reaction.
作者:Tjark H. Meyer、Ramesh C. Samanta、Antonio Del Vecchio、Lutz Ackermann
DOI:10.1039/d0sc05924b
日期:——
Manganaelectro-catalyzed azidation of otherwise inert C(sp3)–H bonds was accomplished using most user-friendly sodium azide as the nitrogen-source. The operationally simple, resource-economic C–H azidation strategy was characterized by mild reaction conditions, no directing group, traceless electrons as the sole redox-reagent, Earth-abundant manganese as the catalyst, high functional-group compatibility
使用大多数用户友好的叠氮化钠作为氮源,完成了锰电催化的惰性 C(sp 3 )–H 键的叠氮化。操作简单、资源经济的C-H叠氮化策略具有反应条件温和、无导向基团、无痕电子作为唯一氧化还原试剂、地球丰富的锰作为催化剂、高官能团相容性和高化学选择性等特点。生物活性化合物的后期叠氮化阶段。通过实验、分光光度法和循环伏安法进行的详细机理研究为金属催化脂肪族自由基的形成以及随后在锰( III / IV )流形内的叠氮基自由基转移提供了强有力的支持。
Catalytic B(C6F5)3H2O-promoted defluorinative functionalization of tertiary aliphatic fluorides
A B(C6F5)3H2O-catalyzed defluorinative functionalization of tertiary aliphaticfluorides is described that proceeds under benign reaction conditions. The synthetic utility of the method is exemplified through the fast and efficient formation of a range of products with newly installed C(sp3) N, S, C and O bonds. This study illustrates the broad reactivity of otherwise inert starting materials and provides
描述了在良性反应条件下进行的AB(C 6 F 5)3 H 2 O催化的叔脂肪族氟化物的脱氟官能化。通过快速有效地形成一系列具有新安装的C(sp 3)N,S,C和O键的产品,可以举例说明该方法的综合用途。这项研究说明了其他惰性原料的广泛反应性,并提供了通往有价值的和合成上代表性不足的产品的途径,这些产品以前从未从此类氟化前体中获得。
Iminophosphorane-mediated transformation of tertiary alcohols into t-alkylamines and their N-phosphorylated derivatives
作者:Anna Koziara、Andrzej Zwierzak
DOI:10.1016/s0040-4039(00)96903-x
日期:1987.1
Novel azidation of tertiary alcohols by means of trimetylsilyl azide in the presence of boron trifluoride etherate has been worked out. The Staudinger reaction of crude azides with triethyl phosphite affords the corresponding iminophosphoranes which can be directly transformed into diethyl N-(t-alkyl) phosphoroamidates or t-alkylamine tosylates.
Nitro-Assisted Brønsted Acid Catalysis: Application to a Challenging Catalytic Azidation
作者:Marian Dryzhakov、Malik Hellal、Eléna Wolf、Florian C. Falk、Joseph Moran
DOI:10.1021/jacs.5b06055
日期:2015.8.5
broad range of substrates. Kineticinvestigations into this surprising effect reveal that nitro compounds induce a switch from first order concentration dependence in Brønsted acid to second order concentration dependence in Brønsted acid and second order dependence in the nitro compounds. Kinetic, electronic, and spectroscopic evidence suggests that higher order hydrogen-bonded aggregates of nitro compounds