A Convenient Synthesis of 1,3-Pyrenedicarbaldehyde

Abstract
A convenient and preparatively useful access to the unknown 1,3-pyrenedicarbaldehyde is presented. When treated with an excess amount of N,N-dimethylformamide and phosphoryl chloride, 3,4-dihydro-2aH-cyclopenta[cd]phenalene was smoothly converted into dialdehyde in 57% yield. A plausible mechanism for this transformation was suggested from a labeling experiment using N,N-dimethylformamide-d7.