Publication
Title
Metal-free synthesis of chlorinated -amino ketones via an unexpected Reaction of imines with arylacetylenes in 1,1,1,3,3,3-hexafluoro-2-propanol
Author
Abstract
The metal-free reaction of terminal arylacetylenes with α,α-dichloroaldimines in 1,1,1,3,3,3-hexafluoro-2-propanol as the sole solvent results in the rapid and selective formation of γ,γ-dichloro-β-amino ketones. In this solvent the expected dichlorinated propargylamines and/or allylic amines are not formed. The dichloromethylene moiety of the aldimine acts as an activating group and is essential to accomplish this transformation. Electron-rich acetylenes lead to the best results and work well with all imines (with or without α′-H at the nitrogen substituent), while electron-deficient acetylenes only reacted with N-tert-butylaldimines (no α′-H). The mechanistic pathway showed 1,1,1,3,3,3-hexafluoro-2-propanol to protonate the aldimine, which in the rate-determining step will react with the arylacetylene to form a resonance-stabilized allene cation, which is trapped by a HFIP molecule giving rise to an enol ether, which promptly hydrolyzes to furnish exclusively the β-amino ketones. Using DFT techniques we found that the first C[BOND]C bond forming step is the rate-determining step and is associated with a barrier of about 21 kcal mol−1.
Language
English
Source (journal)
Advanced synthesis and catalysis. - Weinheim, 2001, currens
Publication
Weinheim : 2016
ISSN
1615-4150 [print]
1615-4169 [online]
Volume/pages
358:1(2016), p. 41-49
ISI
000370256000006
Full text (Publisher's DOI)
UAntwerpen
Faculty/Department
Research group
Publication type
Subject
Affiliation
Publications with a UAntwerp address
External links
Web of Science
Record
Identification
Creation 22.03.2016
Last edited 08.11.2017
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