5460-08-2Relevant articles and documents
Regioselective Arene C?H Alkylation Enabled by Organic Photoredox Catalysis
Holmberg-Douglas, Natalie,Onuska, Nicholas P. R.,Nicewicz, David A.
, p. 7425 - 7429 (2020/03/23)
Expanding the toolbox of C?H functionalization reactions applicable to the late-stage modification of complex molecules is of interest in medicinal chemistry, wherein the preparation of structural variants of known pharmacophores is a key strategy for drug development. One manifold for the functionalization of aromatic molecules utilizes diazo compounds and a transition-metal catalyst to generate a metallocarbene species, which is capable of direct insertion into an aromatic C?H bond. However, these high-energy intermediates can often require directing groups or a large excess of substrate to achieve efficient and selective reactivity. Herein, we report that arene cation radicals generated by organic photoredox catalysis engage in formal C?H functionalization reactions with diazoacetate derivatives, furnishing sp2–sp3 coupled products with moderate-to-good regioselectivity. In contrast to previous methods utilizing metallocarbene intermediates, this transformation does not proceed via a carbene intermediate, nor does it require the presence of a transition-metal catalyst.
Mechanism of the Selective Fe-Catalyzed Arene Carbon-Hydrogen Bond Functionalization
Postils, Verònica,Rodríguez, Mònica,Sabenya, Gerard,Conde, Ana,Díaz-Requejo, M. Mar,Pérez, Pedro J.,Costas, Miquel,Solà, Miquel,Luis, Josep M.
, p. 4313 - 4322 (2018/05/22)
The complete chemoselective functionalization of aromatic C(sp2)-H bonds of benzene and alkyl benzenes by carbene insertion from ethyl diazoacetate was unknown until the recent discovery of an iron-based catalytic system toward such transformation. A Fe(II) complex bearing the pytacn ligand (pytacn = L1 = 1-(2-pyridylmethyl)-4,7-dimethyl-1,4,7-triazacyclononane) transferred the CHCO2Et unit exclusively to the C(sp2)-H bond. The cycloheptatriene compound commonly observed through Buchner reaction or, when employing alkyl benzenes, the corresponding derivatives from C(sp3)-H functionalization are not formed. We herein present a combined experimental and computational mechanistic study to explain this exceptional selectivity. Our computational study reveals that the key step is the formation of an enol-like substrate, which is the precursor of the final insertion products. Experimental evidences based on substrate probes and isotopic labeling experiments in favor of this mechanistic interpretation are provided.
PROCESS FOR PREPARING ARYL- AND HETEROARYLACETIC ACID DERIVATIVES
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Paragraph 0091-0094, (2014/06/23)
The invention relates to a process for preparing aryl- and heteroarylacetic acids and derivatives thereof by reaction of aryl or heteroaryl halides with malonic diesters in the presence of a palladium catalyst, of one or more bases and optionally of a phase transfer catalyst. This process enables the preparation of a multitude of functionalized aryl- and heteroarylacetic acids and derivatives thereof, especially also the preparation of arylacetic acids with sterically demanding substituents.
