Yi-Yun Yu and Gunda I. Georg
The front cover picture, provided by Yi-Yun Yu and Gunda I. Georg, illustrates a novel synthesis of 1,3,5-trisubstituted benzenes from cyclic enaminones featuring a CH functionalization and Diels-Alder tandem sequence. First, the enaminone dienes were constructed atom-economically by a dehydrogenative cross-olefination. This palladium-catalyzed biomimetic CH coupling uses oxygen as the terminal oxidant and proceeds smoothly at room temperature. Then, the enaminone dienes underwent a Diels-Alder tandem reaction to furnish distinct 1,3,5-trisubstituted benzenes, including chalcones, with easily controllable symmetry. This new protocol provides an alternative pathway for arene functionalization. The details are disclosed in the Update by Yu and Georg on pages 1359–1369 (Y.-Y. Yu, G. I. Georg, Adv. Synth. Catal. 2014, 356, 1359–1369; DOI: 10.1002/adsc.201300904).