A catalyst-free benzylic C-H bond olefination of azaarenes for direct Mannich-like reactions.

A highly efficient synthesis of trans-alkenylazaarene under catalyst-free conditions was developed via the addition of methylazaarenes to N-sulfonyl aldimines and a subsequent C-N elimination in situ. A one-pot procedure for this addition-elimination was also developed. The reaction could tolerate a broad substrate scope and give the corresponding alkenylazaarenes in high yields.