CC BY ND NC 4.0 · Synlett 2019; 30(04): 459-463
DOI: 10.1055/s-0037-1611674
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Origins of Contrasteric π-Facial Selectivity in Epoxidations of Encumbered Tetrahydropyridines by a Bifunctional Peracid

,
Sining Wang
,
This work was supported by the National Science Foundation (Grant CHE-1059084 to K. N. H.). XSEDE is supported by the National Science Foundation (Grant OCI-1053575).
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Received: 01. Dezember 2018

Accepted after revision: 21. Januar 2019

Publikationsdatum:
25. Januar 2019 (online)


Published as part of the 30 Years SYNLETT – Pearl Anniversary Issue

Abstract

The origins of contrasteric diastereoselectivity in the epoxidation of encumbered tetrahydropyridines have been elucidated via density functional theory (DFT) calculations. A strong energetic preference for OH···N hydrogen bonding was found for epoxidation transition states of the unsubstituted tetrahydropyridine. For hexasubstituted tetrahydropyridines, the diastereofacial selectivity is dictated by both the strong OH···N hydrogen bonding and the conformational preference of the tetrahydropyridine substrate.

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