Are Allenes with Zwitterionic Character Still Allenes? Of Course!

摘要

In the preceding Correspondence, Christl and Engels have called into question our recent report on cyclic allenes. Their title "Stable Five-Mem-bered-Ring Allenes with Second-Row Elements Only: Not Allenes, But Zwit-terions", gives the reader the impression that we made an incorrect structural assignment. However, reading their article, one can realize that their issues with our work are only semantic in nature. Their concern is that compound 1 is incorrectly named as an allene and incorrectly represented with Lewis structure la. They argue that the aromatic resonance structure 1b represents the ground state of 1, and therefore this compound should be given the very informative designation "a zwitterion derived from pyrazole". As we show below, their semantic and scientific arguments are erroneous.