Chemistry Letters, Vol.43, No.9, 1444-1446, 2014
Regioselective Double Cyclization of 5,15-Bis(trimethylsilylethynyl)porphyrin to Produce Di(oxoethano)porphyrin
Treatment of bis(trimethylsilylethynyl)porphyrin with strong acids afforded doubly oxoethano-fused porphyrin with perfect regioselectivity. The oxoethano-fused porphyrin was more electron deficient than meso-acetylporphyrin because of the coplanar orientation of the carbonyl groups to the porphyrin pi system.