Synthesis 2020; 52(24): 3801-3810
DOI: 10.1055/s-0040-1707294
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Record-Breaking Steric Crowding in Trialkylamines Prepared by Oxidative Ring Opening

Klaus Banert
Organic Chemistry, Chemnitz University of Technology, Strasse der Nationen 62, 09111 Chemnitz, Germany   Email: oc@chemie.tu-chemnitz.de
,
Manuel Heck
,
Andreas Ihle
,
Erik Michael
,
Richard Weber
› Author Affiliations
Generous support by the Deutsche Forschungsgemeinschaft (BA903/17-1) is gratefully acknowledged.


Dedicated to Professor Harald Günther on the occasion of his 85th birthday

Abstract

Epoxidation of olefinic heterocyclic amines and subsequent acid-catalyzed hydrolysis or alternatively the direct dihydroxylation with the help of osmium tetroxide led to diols, which underwent ring cleavage in the presence of lead tetraacetate to give 3-isopropyl-2,2,4,4-tetramethyl-3-azahexanedial and 3-tert-butyl-2,2,4,4-tetramethyl-3-azapentanedial. Whereas the former dialdehyde is a highly unstable model compound because of a rapid intramolecular aldol reaction, the latter product proves to be isolable at room temperature. Furthermore, this compound is the first open-chain tri-tert-alkylamine establishing in a new record of steric crowding in tertiary amines. Strong tendencies to a Hofmann-like elimination reaction or to ring-closing reactions were observed when the aldehyde units of 3-tert-butyl-2,2,4,4-tetramethyl-3-azapentanedial were transformed into other functionalities, since both types of reactions led to a significantly decrease of the steric stress.



Publication History

Received: 01 July 2020

Accepted after revision: 04 August 2020

Article published online:
05 October 2020

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