Porphyrinic pyridinium ylides

Another example with porphyrinic dipolar species uses pyridinium salt derivatives as precursors of porphyrinic pyridinium ylides (Scheme 18) <05TL5487>. The procedure involves the reaction of porphyrin 58 with methyl bromoacetate, in refluxing chloroform, to give pyridinium salt 59. The latter, in the presence of K2CO3, reacts with 1,4-benzoquinone to yield only the mono-addition compound 60. Notably, when the reaction was performed in the presence of DBU, bis-addition occurred and the porphyrinic dimer 61 was the only isolated addition product. 

Scheme 18. 1,3-DC reactions of porphyrinic pyridinium ylide with 1,4-benzoquinone.

Phosphorane Phosphoramidate Phosphorothioate Phthalocyanine Porphyrin Pyran Dihydro Pyrazole Pyridine Dihydro Pyrimidine Dihydro Pyridinium Salt Pyridinium Ylide Pyrrole Pyrrolidine Pyruvic Amide Quinazoline Dihydro... 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

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