Re-Evaluation of a Fulvene-Based Self-Replicating Diels-Alder Reaction System.

We re-evaluate our claim of a high diastereoselectivity in the self-relicating Diels-Alder reaction between maleimide 1 and fulvene 3. It was shown that the system has a diastereoselectivity of 1.8:1 for NN-4:NX-4, which is contrary to the 16:1 ratio claimed by Dieckmann et al. The analysis of 1 H NMR monitoring of the reaction revealed that both replicators show sigmoidal growth which is typical for auto-catalytic systems.