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Ring Opening Reactions of β‐Propiolactam in Superacidic Media
Author(s) -
Beck Stefanie,
Rück Vanessa,
Pietsch LeaViktoria,
Jessen Christoph,
Kornath Andreas J.
Publication year - 2022
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202104086
Subject(s) - protonation , moiety , chemistry , raman spectroscopy , cationic polymerization , salt (chemistry) , ring (chemistry) , solvent , infrared spectroscopy , crystallography , crystal structure , fluoride , infrared , medicinal chemistry , stereochemistry , inorganic chemistry , polymer chemistry , ion , organic chemistry , physics , optics
Abstract The reaction of β‐propiolactam in the superacidic systems HF/ M F 5 ( M =Sb, As) led to the formation of monoprotonated 3‐aminopropanoyl fluoride in the form of [C(O)F(CH 2 ) 2 NH 3 ][SbF 6 ] and [C(O)F(CH 2 ) 2 NH 3 ][AsF 6 ]. In the presence of traces of water, the diprotonated species β‐alanine [C(OH) 2 (CH 2 ) 2 NH 3 ][AsF 6 ] 2 was synthesized for the first time. All salts were characterized by low‐temperature infrared and Raman spectroscopy. Additionally, single‐crystal X‐ray analyses were conducted in the case of [C(O)F(CH 2 ) 2 NH 3 ][SbF 6 ] and [C(OH) 2 (CH 2 ) 2 NH 3 ][AsF 6 ] 2 . By using SO 2 instead of HF as the solvent, the salt [C(OH) 2 (CH 2 ) 2 NHSO][SbF 6 ] 2 was obtained, and single‐crystal X‐ray analysis of this salt containing a thionylimide moiety was conducted. For the formation of these open‐chain compounds, an acyl cationic species as intermediate is assumed, which is formed from N‐protonated β‐propiolactam. Quantum chemical calculations at the B3LYP/aug‐cc‐pVTZ and MP2/aug‐cc‐pVTZ levels of theory were carried out to gain a better understanding of the formation and the structural properties of protonated β‐propiolactam.