Uncommon Phosphonylation of Pyrazine‐2,3‐dicarbonitrile Derivatives via C(sp2)‐CN Bond Cleavage

Asian Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 11, 2024

Abstract A direct phosphonylation of the C(sp 2 )−CN bond under mild catalytic and non‐catalytic reaction conditions is disclosed. Pyrazine‐2,3‐dicarbonitriles are readily coupled with HPO(OEt) to produce corresponding dialkoxyphosphoryl‐substituted pyrazines. The occurs in presence a base (Et 3 N, Cs CO ) as nucleophilic substitution CN groups. yield target diphosphonates depends on nature substituents 5,6‐positions pyrazine ring: it exceeds 90 % for di‐5,6‐aryl‐substituted pyrazines significantly lower when electron‐donating alkyl ( n ‐propyl) groups attached 5,6‐positions. It should be noted that pyrazine‐2,3‐dicarbonitriles bearing vicinal 4‐bromophenyl groups, leading C−CN/P−H coupling ring predominant over Pd‐catalyzed Hirao's C−Br/P−H phenyl rings. Detailed structural characterization, both solution by means 1 H, 13 C 31 P NMR spectroscopy solid state single crystal X‐ray diffraction, series newly synthesized phosphonates reported.

Language: Английский

Photoinduced Regioselective Decarbonylative and Decarboxylative C–O Bond Functionalizations: Approach toward Chemoselective Scissions of Isatoic Anhydride and Unraveling the Enroutes through Control Experiments and DFT Studies

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 5, 2024

Distinctive, green, innovative, and well-organized photoinduced (metal- or photocatalyst-free) regioselective decarbonylative decarboxylative C–O bond functionalization protocols to access aryl 2-aminobenzoates 2-substituted benzoxazinone derivatives in excellent yields have been devised. These are achieved through the chemoselective scission of isatoic anhydride with ketones, diaryliodonium triflate, nitroalkene, phthalazinone, phenol derivatives, which, turn, served as representative "electrophilic nucleophilic" coupling partners. Control experiments DFT calculations reveal that electrophilic radical-bearing partners specifically follow decarbonylation pathway, while nucleophilic conjugates facilitate decarboxylation process. Thus, devised methods represent fragmentation anhydride, which occurs due electronic nature Again, C–O/O–C formation is also a novel outcome this methodology. We green method for synthesizing 2-aminobenzoate-subtituted paracetamol route. A fluorescence quenching study indicates phenyl 2-aminobenzoate detects Fe(II) ions, exhibiting no reactivity toward various other metal ions. Additionally, transition-metal-catalyzed C–H vinyl sulfone was performed at ease significant yields, appreciated strategy developed by us.

Language: Английский