Vilsmeier formylation of 5,10,15-triphenylcorrole: expected and unusual products.
5,10,15-Triphenylcorrole (1) reacts with the Vilsmeier reagent (POCl(3)/DMF) to give the corresponding 3-formyl derivative 3 as the major product. The regioselectivity of the reaction was proven by X-ray crystallography and only traces of the 2-formyl isomer were observed. A more polar product is also observed and this compound becomes the major product when an excess of DMF is used for the preparation of the Vilsmeier reagent, while the formation of the 3-formyl isomer is almost completely suppressed. X-ray crystallography allowed us to identify this compound as the fully substituted N-ethane bridged derivative 4, formed from the attack of the Vilsmeier reagent at the inner core of the macrocycle. This compound is unique among porphyrinoid macrocycles, and further confirms the peculiarity of corrole chemistry.
Paolesse
Roberto
R
Dipartimento di Scienze e Tecnologie Chimiche Università di Roma Tor Vergata and CNR-IMM 00133 Roma, Italy. roberto.paolesse@uniroma2.it
Nardis
Sara
S
Venanzi
Mariano
M
Mastroianni
Marco
M
Russo
Michele
M
Fronczek
Frank R
FR
Vicente
Maria Graça H
MG