Calcium‐Catalyzed Cyclopropanation

No transition metal needed: A calcium-catalyzed cycloisomerization yields highly substituted cyclopropanes with excellent diastereoselectivity (see scheme; Nu=nucleophile, Ts=p-toluenesulfonyl). The reaction is based on the equilibrium of a homoallenyl cation with its cyclopropane congener, which is known for gold-catalyzed reactions. According to mechanistic analysis the carbocation cascade is concerted asynchronous, and hence biomimetic. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to 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.