<i>N</i>‐Heterocyclic‐Carbene‐Catalyzed Reaction of α‐Bromo‐α,β‐Unsaturated Aldehyde or α,β‐Dibromoaldehyde with Isatins: An Efficient Synthesis of Spirocyclic Oxindole–Dihydropyranones

Abstract

Smooth as isatin! A straightforward synthesis of spirocyclic oxindole–dihydropyranones through an N-heterocyclic-carbene-catalyzed [4+2] annulation of α-bromo-α,β-unsaturated aldehydes or α,β-dibromoaldehyde bearing γ-H with isatin derivatives under mild reaction conditions is disclosed (see scheme). The concise construction, ready availability of the starting materials, avoidance of external oxidants, and the potential utilization value of final products in molecular biology and pharmacy makes this approach particularly attractive. 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.