Mark Stradiotto
Angewandte Chemie International Edition,
May 22, 2018, Letnik:
57, Številka:
21
Journal Article
Recenzirano
“My favorite name reaction is the Buchwald–Hartwig amination. If I had one year of paid leave I would travel the world ...” This and more about Mark Stradiotto can be found on page 5986.
Kilian Muñiz (1970–2020) Streuff, Jan; Echavarren, Antonio M.; González, José Manuel ...
Angewandte Chemie International Edition,
May 11, 2020, Letnik:
59, Številka:
20
Journal Article
Recenzirano
Kilian Muñiz passed away unexpectedly on March 16th, 2020, at the age of only 49. Kilian was a leading figure in the field of catalytic (di‐)amination reactions. He will be remembered as one of the ...finest, most passionate chemists, a dear colleague, and, most of all, as a close friend.
Easy on, easy off: Directing groups found to promote the palladium‐catalyzed amination of γ C(sp3)H and C(sp2)H bonds of secondary amides included 5‐methoxy‐8‐aminoquinoline, which can be removed ...under mild conditions (see scheme; CAN=ceric ammonium nitrate). In conjunction with a β‐CH methylation or γ‐CH arylation step, the γ‐C(sp3)H amination provided access to complex pyrrolidones from readily available precursors.
A modular approach to prepare tri- and tetracyclic carbazoles by a sequential 3 + 2heteroannulation is described. First, optimization of Pd-catalyzed Buchwald-Hartwig amination followed by ...C/N-arylation in a one-pot process is established. Second, mechanistic analyses identified the origins of chemo- and regioselective sequential control of both bond-forming steps. Finally, the substrate scope is demonstrated by the preparation of a range of tri- and tetracyclic carbazoles, including expedient access to several natural products and anti-cancer agents.
The nucleophilic iron complex Bu4NFe(CO)3(NO) (TBAFe) catalyzes the direct intramolecular amination of unactivated C(sp3)−H bonds in alkylaryl azides, which results in the formation of substituted ...indoline and tetrahydroquinoline derivatives.
What a surprise: The anionic iron complex Bu4NFe(CO)3(NO) catalyzes the denitrogenative C(sp3)−H amination of a variety of alkylaryl azides to the corresponding indolines and, unexpectedly, tetrahydroquinolines in good yields.
The direct conversion of aliphatic CH bonds into CN bonds provides an attractive approach to the introduction of nitrogen-containing functionalities in organic molecules. Following the recent ...discovery that cytochrome P450 enzymes can catalyze the cyclization of arylsulfonyl azide compounds via an intramolecular C(sp3)H amination reaction, we have explored here the CH amination reactivity of other hemoproteins. Various heme-containing proteins, and in particular myoglobin and horseradish peroxidase, were found to be capable of catalyzing this transformation. Based on this finding, a series of engineered and artificial myoglobin variants containing active site mutations and non-native Mn- and Co-protoporphyrin IX cofactors, respectively, were prepared to investigate the effect of these structural changes on the catalytic activity and selectivity of these catalysts. Our studies showed that metallo-substituted myoglobins constitute viable CH amination catalysts, revealing a distinctive reactivity trend as compared to synthetic metalloporphyrin counterparts. On the other hand, amino acid substitutions at the level of the heme pocket were found to be beneficial toward improving the stereo- and enantioselectivity of these Mb-catalyzed reactions. Mechanistic studies involving kinetic isotope effect experiments indicate that CH bond cleavage is implicated in the rate-limiting step of myoglobin-catalyzed amination of arylsulfonyl azides. Altogether, these studies indicate that myoglobin constitutes a promising scaffold for the design and development of CH amination catalysts.
The direct replacement of sp
C-H bonds with simple amine units (-NH
) remains synthetically challenging, although primary aliphatic amines are ubiquitous in medicinal chemistry and natural product ...synthesis. We report a mild and selective protocol for preparing primary and secondary aliphatic amines in a single pot, based on intermolecular sp
C-H imination. The first C-H imination of diverse alkanes, this method shows useful site-selectivity within substrates bearing multiple sp
C-H bonds. Furthermore, this reaction tolerates polar functional groups relevant for complex molecule synthesis, highlighted in the synthesis of amine pharmaceuticals and amination of natural products. We characterize a unique C-H imination mechanism based on radical rebound to an iminyl radical, supported by kinetic isotope effects, stereoablation, resubmission, and computational modeling. This work constitutes a selective method for complex amine synthesis and a new mechanistic platform for C-H amination.
Molecular desalination is broadly used in chemical, food, and textile industries, which needs efficient and anti‐fouling separation technologies to reach this goal. Interfacial polymerization is one ...of the most promising routes to construct ultrahigh selective nanofiltration membranes. However, the irreversible hydrolysis of residual acyl chlorides makes Donnan charges of nascent films distribute unevenly which hinders fine molecular desalination and anti‐fouling. Here, we propose a pioneering solvation‐amination‐synergy strategy to synchronously inhibit the hydrolysis of residual acyl chlorides and promote their amination. The electroneutral nanofiltration membrane with high water permeance (13.2 L m−2 h−1 bar−1) is quantitatively fabricated that has superb anti‐fouling abilities and minimizes Donnan impacts on competitive ion penetrations, so it transmits Na2SO4 and NaCl while fully obstructs cationic or anionic dyes (< 500 Da). The ultrahigh molecule to ion selectivities outperform state‐of‐art nanofiltration membranes, which may provide a paradigm shift for scalable membrane fabrication for various industrial product desalination.
A new method for metal‐free intramolecular CH amination has been developed. Electrochemical oxidation of 2‐pyrimidyloxybenzenes and 2‐pyrimidylthiobenzenes, which can be easily prepared from phenols ...and thiophenols, respectively, followed by the treatment of the resulting pyrimidinium ions with piperidine gives 2‐aminobenzoxazoles and 2‐aminobenzothiazoles, respectively.
Integration of electrochemical and chemical reactions: A new method for metal‐free intramolecular CH amination has been developed. Electrochemical oxidation of 2‐pyrimidyloxybenzenes and 2‐pyrimidylthiobenzenes, which can be easily prepared from phenols and thiophenols, respectively, followed by the treatment of the resulting pyrimidinium ions with piperidine gives 2‐aminobenzoxazoles and 2‐aminobenzothiazoles, respectively.
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