无保护基团转化是原子经济有机合成中一个具有挑战性和重要的问题。η(6)-芳烃/N-Me-磺酰二胺-Ru(II)-BF4 配合物催化2-取代的未保护吲哚在弱酸性六氟异丙醇中的不对称氢化得到具有高达>99% ee 的旋光二氢吲哚化合物。在温和的反应介质下,吲哚上的卤素原子和合成上重要的保护基团(例如甲硅烷基醚、缩醛、苄基醚和酯)得以保留,这有利于进一步合成复杂的二氢吲哚分子。
Asymmetric Hydrogenation of Unprotected Indoles Catalyzed by η<sup>6</sup>-Arene/<i>N</i>-Me-sulfonyldiamine–Ru(II) Complexes
作者:Taichiro Touge、Takayoshi Arai
DOI:10.1021/jacs.6b06295
日期:2016.9.7
Protecting-group-free transformation is a challenging and important issue in atom-economical organic synthesis. The η(6)-arene/N-Me-sulfonyldiamine-Ru(II)-BF4 complex-catalyzed asymmetric hydrogenation of 2-substituted unprotected indoles in weakly acidic hexafluoroisopropanol gives optically active indoline compounds with up to >99% ee. Under mild reaction media, halogen atoms and synthetically important
无保护基团转化是原子经济有机合成中一个具有挑战性和重要的问题。η(6)-芳烃/N-Me-磺酰二胺-Ru(II)-BF4 配合物催化2-取代的未保护吲哚在弱酸性六氟异丙醇中的不对称氢化得到具有高达>99% ee 的旋光二氢吲哚化合物。在温和的反应介质下,吲哚上的卤素原子和合成上重要的保护基团(例如甲硅烷基醚、缩醛、苄基醚和酯)得以保留,这有利于进一步合成复杂的二氢吲哚分子。
Pd-Catalyzed Asymmetric Hydrogenation of Unprotected Indoles Activated by Brønsted Acids
The first highly enantioselective hydrogenation of simple indoles was developed with a Brønstedacid as an activator to form the iminium intermediate in situ, which was hydrogenated using Pd(OCOCF(3))(2)/(R)-H8-BINAP catalyst system with up to 96% ee. The present method provides an efficient route to enantioenriched 2-substituted and 2,3-disubstituted indolines.
Kinetic Resolution of 2-Substituted Indolines by <i>N</i>
-Sulfonylation using an Atropisomeric 4-DMAP-<i>N</i>
-oxide Organocatalyst
作者:James I. Murray、Nils J. Flodén、Adriano Bauer、Nico D. Fessner、Daniel L. Dunklemann、Opetoritse Bob-Egbe、Henry S. Rzepa、Thomas Bürgi、Jeffery Richardson、Alan C. Spivey
DOI:10.1002/anie.201700977
日期:2017.5.15
The first catalytic kinetic resolution by N‐sulfonylation is described. 2‐Substituted indolines are resolved (s=2.6–19) using an atropisomeric 4‐dimethylaminopyridine‐N‐oxide (4‐DMAP‐N‐oxide) organocatalyst. Use of 2‐isopropyl‐4‐nitrophenylsulfonyl chloride is critical to the stereodiscrimination and enables facile deprotection of the sulfonamide products with thioglycolic acid. A qualitative model
98% ee using a strong Brønsted acid as the activator. This methodology was applied in the facile synthesis of biologically active products containing a chiral indoline skeleton. The mechanism of Pd-catalyzed asymmetric hydrogenation was investigated as well. Isotope-labeling reactions and ESI-HRMS proved that an iminium salt formed by protonation of the C═C bond of indoles was the significant intermediate
Asymmetric hydrogenation of unprotected indoles using iridium complexes derived from P–OP ligands and (reusable) Brønsted acids
作者:José Luis Núñez-Rico、Héctor Fernández-Pérez、Anton Vidal-Ferran
DOI:10.1039/c3gc42132e
日期:——
stepwise process: (reusable) Brønsted acid-mediated CC isomerisation and asymmetrichydrogenationusing enantioselective iridium catalysts derived from P–OP ligands. This straightforward combination of (reusable) Brønstedacids, which activate the indole ring for hydrogenation by breaking its aromaticity, and enantiomerically pure [Ir(P–OP)]+ complexes as hydrogenation catalysts affords the resulting