Brouder, Thomas A.; Slattery, Catherine N.; Ford, Alan; Khandavilli, U. B. Rao; Skořepová, Eliška; Eccles, Kevin S.; Lusi, Matteo; Lawrence, Simon E.; Maguire, Anita R.

2019

Unknown

The Journal of Organic Chemistry

Desymmetrization by Asymmetric Copper-Catalyzed Intramolecular C–H Insertion Reactions of a-Diazo-ß-oxosulfones

Published

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Copper-catalyzed Asymmetric

Effective desymmetrization in copper-catalyzed intramolecular C–H insertion reactions of a-diazo-ß-oxosulfones in the formation of fused thiopyran dioxides is described for the first time. The use of a copper–bis(oxazoline)–NaBARF catalyst complex system leads to formation of the major thiopyran dioxide stereoisomer with up to 98:2 dr and up to 98% ee. The effect of varying the bis(oxazoline) ligand, copper salt, and site of C–H insertion on both diastereo- and enantioselectivities of these intramolecular C–H insertion reactions has been investigated. Similarly, desymmetrization in the formation of a fused cyclopentanone proceeds with up to 64% ee. These results represent the highest enantioselectivity reported to date in a copper-mediated desymmetrization through C–H insertion.

0022-3263

https://pubs.acs.org/doi/10.1021/acs.joc.8b03160

10.1021/acs.joc.8b03160