Highly Enantioselective [3+2] Annulation of Morita–Baylis–Hillman Adducts Mediated by L‐Threonine‐Derived Phosphines: Synthesis of 3‐Spirocyclopentene‐2‐oxindoles having Two Contiguous Quaternary Centers

Spiral bound: The Morita–Baylis–Hillman adducts were employed as C3 synthons in the asymmetric [3+2] annulation with malonitrile substrates using L-threonine-derived 1 as the catalyst (see scheme). The reaction is highly regioselective and stereoselective, and affords optically enriched 3-spirocyclopentene-2-oxindoles containing two contiguous quaternary centers. Boc=tert-butoxycarbonyl, PMB=para-methoxybenzyl, TIPS=triisopropylsilyl. 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.