Gold(I)-Catalyzed Highly Diastereo- and Enantioselective Cyclization-[4+3] Annulation Cascades between 2-(1-Alkynyl)-2-alken-1-ones and Anthranils

Rahul Dadabhau Kardile; Tzu-Hsuan Chao; Mu-Jeng Cheng; Rai-Shung Liu

doi:10.1002/anie.202001854

Gold(I)-Catalyzed Highly Diastereo- and Enantioselective Cyclization-[4+3] Annulation Cascades between 2-(1-Alkynyl)-2-alken-1-ones and Anthranils

Angew Chem Int Ed Engl. 2020 Jun 22;59(26):10396-10400. doi: 10.1002/anie.202001854. Epub 2020 Apr 15.

Authors

Rahul Dadabhau Kardile¹, Tzu-Hsuan Chao², Mu-Jeng Cheng², Rai-Shung Liu¹

Affiliations

¹ Frontier Research Center on Fundamental and Applied Sciences of Matters, Department of Chemistry, National Tsing-Hua University, Hsinchu, Taiwan, ROC.
² Department of Chemistry, National Cheng Kung University, East District, Tainan City, Taiwan, ROC.

PMID: 32212225
DOI: 10.1002/anie.202001854

Abstract

This work reports gold-catalyzed [4+3]-annulations of 2-(1-alkynyl)-2-alken-1-ones with anthranils to yield epoxybenzoazepine products with excellent exo-diastereoselectivity (dr>25:1). The utility of this new gold catalysis is manifested by applicable substrates over a broad scope. More importantly, the enantioselective versions of these [4+3]-cycloadditions have been developed satisfactorily with chiral gold catalysts under ambient conditions (DCM, 0 °C); the ee levels range from 88.0-99.9 %. With DFT calculations, we postulate a stepwise pathway to rationalize the preferable exo-stereoselection.

Keywords: annulation; anthranils; enantioselectivity; epoxybenzoazepines; gold.

Abstract

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