Cover Feature: Programmed Site‐Selective Palladium‐Catalyzed Arylation of Thieno[3,2‐b]thiophene (Chem. Asian J. 21/2017)

An efficient and straightforward method for the synthesis of multi‐arylated thieno[3,2‐b]thiophene is reported. The direct site‐selective arylation of 2‐arylthieno[3,2‐b]thiophene takes place at predictable positions (i.e., at the C‐3 or C‐5 position) depending on the nature and the size of the 2‐aryl substituents. If the 2‐aryl substituent bears an electron‐withdrawing group, the next arylation takes place at the C‐3 position. On the other hand, if the 2‐aryl substituent bears an electron‐donating group, the next arylation takes place at the C‐5 position. More information can be found in the Full Paper by Tung Thanh Dang, Hien Nguyen et al. on page 2819 in Issue 21, 2017 (DOI:10.1002/asia.201700562).