Ligand-Enabled C6-Selective C-H Arylation of Pyrrolo[2,3-d] Pyrimidine Derivatives with Pd Catalysts: An Approach to the Synthesis of EGFR Inhibitor AEE-788

Herein, we report the Pd(II)-catalyzed direct C-H arylation of pyrrolo[2,3-d]pyrimidine derivatives with aryl iodides, which is enabled by bidentate pyridine-pyridine ligands. A range of aryl iodides proved to be suitable coupling partners affording the desired products in good yields with high levels of C6 selectivity. This protocol features good tolerance of reactive functional groups, mild reaction conditions, and a simple reaction system, which provides an expeditious route to an essential class of 6-arylpyrrolo[2,3-d]pyrimidines frequently found in bioactive compounds, and provides a step-economical access to the second-generation EGFR inhibitor AEE-788.

Visible-Light-Induced Highly Site-Selective Direct C-H Phosphorylation of Pyrrolo[2,3-d]pyrimidine Derivatives with H-Phosphine Oxides

An efficient and highly regioselective C6-phosphorylation protocol for pyrrolo[2,3-d]pyrimidine (7-DAP) derivatives with various H-phosphine oxides induced by visible light at room temperature is described for the first time. This protocol has been successfully achieved by the combination of Na2-eosin Y as a photocatalyst and LPO as an oxidant under transition metal- and additive-free conditions. The broad substrate scope, good functional group tolerance, excellent regioselectivity, and air tolerant conditions make this process favorable for the functional modification of pyrrolo[2,3-d]pyrimidine scaffold and enrich the phosphorylated 7-DAP compounds for further biological evaluation.

Ru(II)-Catalyzed Synthesis of Fused Imidazo[1,2-a]pyridine-chromenones and Methylene-Tethered Bis-imidazo[1,2-a]pyridines and Regioselective O-Acetoxylation of Imidazo[1,2-a]pyridines

Herein, we disclose an unprecedented protocol via ruthenium-catalyzed annulation for the synthesis of 6H-chromeno[4',3':4,5]imidazo[1,2-a]pyridin-6-one, and functionalized 2-(3-formylimidazo[1,2-a]pyridin-2-yl)phenyl acetate has been revealed by intramolecular chelation-assisted C-H activation. Additionally, a one-pot approach for creating bis(2-phenylimidazo[1,2-a]pyridin-3-yl)methane (BIP) has been realized through ruthenium catalysis with the use of formic acid. This method was used in gram-scale synthesis of BIP and step-economical late-stage functionalization of a marketed drug, zolimidine, in good yield.

Updates on hypervalent-iodine reagents in metal-free organic synthesis

Hypervalent iodine (HVI) chemistry is a rapidly growing subdomain of contemporary organic chemistry because of its enormous synthetic applications. The high nucleofugality of the phenyliodonio group (I+Ph) and their radical...

Pd-Catalyzed solvent-controlled site-selective arene C-H monoacyloxylation of pyrrolo[2,3-d]pyrimidine derivatives

An efficient and highly regioselective Pd-catalyzed direct arene C(sp²)-H acyloxylation of pyrrolo[2,3-d]pyrimidine derivatives is reported. The key strategy involves the utilization of the unique reactivity of pyrrolo[2,3-d]pyrimidine and the employment of pyrrolo[2,3-d]pyrimidine as the directing group. A variety of monoacyloxylated pyrrolo[2,3-d]pyrimidine derivatives can be achieved by switching the solvents under mild conditions, and they can be further modified and exhibit various biological activities.

An isoxazole strategy for the synthesis of alkyl 5-amino-4-cyano-1H-pyrrole-2-carboxylates - versatile building blocks for assembling pyrrolo-fused heterocycles

A full atom-economical domino method has been developed for the preparation of alkyl 5-amino-4-cyano-1H-pyrrole-2-carboxylates by transannulation of 5-alkoxyisoxazoles with malononitrile under Fe(ii) catalysis. Alkyl 5-amino-4-cyano-1H-pyrrole-2-carboxylates are excellent building blocks for various annulation reactions, leading to new derivatives of 1H-pyrrolo[1,2-a]imidazole and pyrrolo[2,3-d]pyrimidine. The DFT calculations of mechanistic details of alkyl 5-amino-4-cyano-1H-pyrrole-2-carboxylate formation are presented.