Combining aromaticity and hyperconjugation, two important concepts in organic chemistry, leads to hyperconjugative aromaticity, which was first proposed by Mulliken in 1939. However, previous studies on hyperconjugative aromaticity have mainly focused on substituents containing either main-group elements (group 14) or transition metals in groups 7, 9, 10, and 11. In this study, we perform density functional theory (DFT) calculations on cyclopentadiene and pyrrolium derivatives containing groups 13, 15 and 16 substituents to examine the possibility of achieving hyperconjugative aromaticity.

In most Suzuki-Miyaura carbon-carbon cross-coupling reactions, the borabicyclo[3.3.1]nonane scaffold (9-BBN) only serves as an auxiliary facilitating the transmetalation step and thus is transformed into by-products. There are rare examples where the 9-BBN derivatives serve as the potentially diverse C8 building blocks in cross-coupling reactions. Herein, we report a cobalt-catalyzed migratory carbon-carbon cross-coupling reaction of the in situ formed 9-BBN ate complexes to afford diverse aryl- and alkyl-functionalized cyclooctenes.