19472-74-3Relevant articles and documents
Divergent synthesis of CF3-substituted polycyclic skeletons based on control of activation site of acid catalysts
Yokoo, Kazuma,Mori, Keiji
, p. 6927 - 6930 (2018)
We report a divergent synthesis of CF3-substituted fused skeletons based on precise control of the activation site through the selection of acid catalysts. When trifluoromethyl ketones with an ortho-phenethyl ether group were treated with a catalytic amount of Sc(OTf)3, a hydride shift triggered C(sp3)-H bond functionalization proceeded to give CF3-substituted isochromene derivatives by selective activation of the carbonyl group. In sharp contrast, CF3-substituted bicyclo[3.3.1]nonanes were obtained exclusively via the activation of ether oxygen initiated sequential reactions (nucleophilic attack of carbonyl oxygen, and intramolecular Friedel-Crafts reaction) under strong Br?nsted acid catalysis (Tf2NH).
The palladium(ii)-catalyzed regioselective ortho-C-H bromination/iodination of arylacetamides with in situ generated imidic acid as the directing group: Mechanistic exploration
Jaiswal, Yogesh,Kumar, Yogesh,Kumar, Amit
, p. 6809 - 6820 (2019/07/22)
In the present study, we report the palladium(ii)-catalyzed regioselective ortho-C-H bromination/iodination of challenging arylacetamide derivatives using N-halosuccinimides as halogenating agents. Diverse arylacetamides underwent the regioselective ortho-bromination and iodination of aromatic C-H bonds in the presence of a reactive benzylic C(sp3)-H bond without installing any bulky auxiliaries via unfavorable six-membered metallacycles. Weak coordination, the use of ubiquitous primary amides for challenging C-H functionalization, the simple catalytic system and the wide substrate scope are the key features of this transformation. Further, the halogenated amide derivatives were transformed into a variety of valuable synthons. Detailed mechanistic studies revealed some interesting aspects concerning the reaction pathway. We present for the first time strong evidence for the formation of imidic acid (in situ) from primary amides under Br?nsted acid conditions that eventually aids in the stabilization of palladacycles of amide derivatives and drives regioselective C-X bond formation.
Chiral Magnesium Bisphosphate-Catalyzed Asymmetric Double C(sp3)-H Bond Functionalization Based on Sequential Hydride Shift/Cyclization Process
Mori, Keiji,Isogai, Ryo,Kamei, Yuto,Yamanaka, Masahiro,Akiyama, Takahiko
supporting information, p. 6203 - 6207 (2018/05/23)
Described herein is a chiral magnesium bisphosphate-catalyzed asymmetric double C(sp3)-H bond functionalization triggered by a sequential hydride shift/cyclization process. This reaction consists of stereoselective domino C(sp3)-H bond functionalization: (1) a highly enantio- and diastereoselective C(sp3)-H bond functionalization by chiral magnesium bisphosphate (first [1,5]-hydride shift), and (2) a highly diastereoselective C(sp3)-H bond functionalization by an achiral catalyst (Yb(OTf)3, second [1,5]-hydride shift).