Herein we describe a general, mild and scalable method for deuterium incorporation by potassium methoxide/hexamethyldisilane-mediated dehalogenation of arylhalides. With CDCN as a deuterium source, a wide array of heteroarenes prevalent in pharmaceuticals and bearing diverse functional groups are labeled with excellent deuterium incorporation (>60 examples). The ipso-selectivity of this method provides precise access to libraries of deuterated indoles and quinolines. The synthetic utility of our method has been demonstrated by the incorporation of deuterium into complex natural and drug-like compounds.
An iron-catalyzed asymmetric oxidative homo-coupling of 2-naphthols for the synthesis of 1,1′-Bi-2-naphthol (BINOL) derivatives is reported. The coupling reaction provides enantioenriched BINOLs in good yields (up to 99%) and moderate enantioselectivities (up to 81:19 er) using an iron-complex generated in situ from Fe(ClO4)2 and a bisquinolyldiamine ligand [(1R,2R)-N1,N2-di(quinolin-8-yl)cyclohexane-1,2-diamine, L1]. A number of ligands (L2–L8) and the analogs of L1, with various substituents and chiral backbones, were synthesized and examined in the oxidative coupling reactions.
A copper-catalyzed annulation of alkyne-tethered enaminones
for
the synthesis of 2,3-ring fused pyrroles is reported. The 5-exo-dig cyclization/olefin migration reaction delivers the
multisubstituted pyrroles in 59–99% yields with 16 examples.
This strategy features easily available starting materials, mild reaction
conditions, and a cheap ligand-free copper catalyst. The atom-economic
transformation provides a simple access to a variety of synthetic
useful pyrroles and their derivatives.
C-H activation | Amination |Cyclization | Iron catalysis | Nitrene insertion A redox-neutral Fe-catalyzed intramolecular C-H amidation of N-benzoyloxyureas is described. This methodology employs a simple iron complex in situ generated from Fe(OTf) 2 and bipyridine as the catalyst and N-benzoyloxyureas as the nitrene precursors without using exogenous oxidants. An array of cyclic ureas were synthesized via aliphatic C(sp 3)-H amidation in excellent yields. In addition, this catalytic system is also amenable to aryl C(sp 2)-H nitrene insertion to provide benzimidazolones in moderate yields.
Transition-metal-nitrenoids intramolecular C-H insertion is one of the most effective methods to synthesize nitrogen-containing heterocycles. Using 2-azido-N,N-dibenzylacetamides as substrates, an iron-catalyzed intramolecular C(sp 3 )-H bond amination reaction under ligand-free and external oxidant-free conditions has been developed. A series of imidazolinones were synthesized in moderate to good yields.
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