Pronounced Chemo-, Regio-, and Stereoselective [2 + 2] Cycloaddition Reaction of Allenes toward Alkenes and Alkynes

摘要

In summary, the allenes 1a -c readily undergo thermal [2 + 2] additions with alkenes and alkynes with pronounced chemo, regio-, and stereoselectivities. The alkenes encompass ethylenes bearing not only electron-attracting and conjugating groups but also electron-donating groups. Even 1, 3-dienes are engaged in exclusive [2 + 2] addition reactions.