(Cyanoviny1) pyrroles (13) derived from the Knoevenagel condensation of benzyl 5-formyl-2- pyrrolecarboxylates (12) with methyl cyanoacetate were employed in a facile sequence of four steps to produce, regioselectively, 5-unsubstituted 2-pyrrolecarboxaldehydea (5), important intermediates for porphyrin synthesis. Each step proceeded in 90-95% yield, making 5 available smoothly from benzyl 5-methyl-2-pyrrolecarboxylates (10) in seven ...
