An Enolate‐Structure‐Enabled Anionic Cascade Cyclization Reaction: Easy Access to Complex Scaffolds with Contiguous Six‐, Five‐, and Four‐Membered Rings
- 22 July 2020
- journal article
- research article
- Published by Wiley in Angewandte Chemie-International Edition
- Vol. 59 (45), 20120-20128
- https://doi.org/10.1002/anie.202008317
Abstract
Catalyst‐free addition of ketone enolate to non‐activated multiple C‐C bonds involves non‐complementary reaction partners and typically requires super‐basic conditions. On the other hand, highly aggregated or solvated enolates are not reactive enough to undergo direct addition to alkenes or alkynes. Herein, we report a new anionic cascade reaction for one‐step assembly of intriguing molecular scaffolds possessing contiguous six‐, five‐ and four‐membered rings, representing a formal [2+2] enol‐allene cycloaddition. Reaction proceeds under very mild conditions and with excellent diastereoselectivity. Deeper mechanistic and computational studies revealed unusually slow proton transfer phenomena in cyclic ketone intermediate and explained peculiar stereochemical outcome.Keywords
Funding Information
- Lietuvos Mokslo Taryba (S-MIP-17-46)
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