摘要
Carbocycles are ubiquitous in natural organic molecules and medicinal agents. Therefore, developing methodologies for the efficie nt con struction of car bo cycles constitutes an importa nt goal in organic synthesis. In this regard, for the construction of sixmembered rings, the Diels-Alder [4+2] cycloaddition reaction (Figure 1, eq 1) and Robinson annulation (Figure 2, eq 1) represent two paradigms in terms of efficiency, selectivity, and versatility.