An efficient room‐temperature visible‐light photoredox α‐acyloxyalkylation reaction of N‐heteroarenes is reported, which relies on the use of ethyl acetate as a cheap and non‐conventional radical source. The direct C(sp2)‐C(sp3) coupling was extended to a diverse set of mono‐, bi‐, and tricyclic of N‐heteroaromatics, and the optimized photoredox protocol was successfully performed on a multigram scale. The scope of the alkylating agent was also explored and a plausible mechanism was proposed, involving photoinduced single‐electron transfer and hydrogen‐atom transfer processes.
The Spin-Center Shift (SCS) elimination is a specific
way for the
generation of radicals with relevance in synthetic and biochemical
pathways. The combination of SCS-mediated radical chemistry and atom-transfer
radical addition (ATRA) offers new directions in diversity-oriented
chemical synthesis. Herein, we report a photoredox three-component
reaction of α-acyloxy-N-heterocycles as radical
precursors, styrene derivatives as radical trapping agents, and alcohols
as nucleophilic quenchers. The novel radical-polar crossover reaction
provides access to a diverse set of branched ethers possessing high
structural complexity. The utility of the transformation was also
demonstrated by the synthesis of a complex drug derivative and it
was easily scalable to the multigram level. The scope and limitations
were also explored and a plausible mechanism was proposed.
The trifluoromethylation of aromatic and heteroaromatic cores has attracted considerable interest in recent years due to its pharmacological relevance. We studied the extension of a simple copper-catalyzed trifluoromethylation protocol to alkoxy-substituted iodopyridines and their benzologs. The trifluoromethylation proceeded smoothly in all cases, and the desired compounds were isolated and characterized. In the trifluoromethylation of 3-iodo-4-methoxyquinoline, we observed a concomitant O-N methyl migration, resulting in the trifluoromethylated quinolone as a product. Overall, the described procedure should facilitate the broader use of copper-catalyzed trifluoromethylation in medicinal chemistry.
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