Synthesis of Nine‐Membered Carbocycles by the [4+3+2] Cycloaddition Reaction of Ethyl Cyclopropylideneacetate and Dienynes

Various dienynes reacted efficiently with ethyl cyclopropylideneacetate in the presence of [Ni(cod)2]/PPh3, and cyclononadienes were synthesized in a selective manner. Dienynes tethered with aromatic rings were very good substrates, and the corresponding tricyclic compounds were isolated in high yields. The reaction provides a new route for the synthesis of nine-membered carbocycles (see scheme). Detailed facts of importance to specialist readers are published as "Supporting Information". Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.