14387-96-3Relevant articles and documents
Regioselectivity in nucleophilic ring-opening of aziridinones
Talaty, Erach R.,Yusoff, Mashitah M.
, p. 985 - 986 (1998)
The proportions of products derived from competing modes of ring-opening of 1,3-di-tert-butylaziridinone and similar aziridinones by a variety of nitrogen, oxygen, sulfur and halogen nucleophiles do not agree with simple guidelines postulated in the liter
stereochemistry of Ring Opening of Aziridinones (α-Lactams)
Quast, Helmut,Leybach, Holger
, p. 2105 - 2112 (2007/10/02)
The chiral, non-racemic aziridinone (R)-4 (e.e.92percent) reacts with magnesium halides to afford the α-halo amides (S)-3a (e.e. 88.8percent), (S)-3b (e.e. 89.0percent), and (S)-3c (e.e. 88.2percent) in high yields.Acid-catalyzed hydrolysis of (R)-4 in aqueous acetone yields 74percent of the α-hydroxy amide (S)-3d (e.e. 88.0percent).Methanolysis of (R)-4 in methanol at 60 deg C followed the first-order rate law with k = 1.53 * 10-5s-1 yielding quantitatively a 82:18 mixture of the α-methoxy amide (S)-3e (e.e. 89percent) and the α-amino ester (R)-14 (e.e. 87percent) when (R)-4 reacts with sodium methoxide and methanol in ether while only the former is formed (e.e. 88.2percent) byslow methanolysis in the presence of a catalytic amount of 4-toluenesulfonic acid.The absolute configurations of the major enantiomers derived from (R)-4 are based on the retention on a Chirasil-L-Val capillary gas chromatography column, CD spectra, and the comparison with authentic samples of (S)-3a, obtained from (S)-tert-leucine and (S)-3d.The results demonstrate that the N-C(3) bond of the aziridione (R)-4 is cleaved by nucleophiles with a high degree of stereospecificity and inversion of configuration.This stereochemical course is at variance with that inferred from the methanolysis of the similar aziridinone (R)-7. - Treatment of (R)-4 in methanol with one equivalent of 3-chloroperbenzoic acid (15) containing 5percent of 3-chlorobenzoic acid (16) affords carbon monoxide and the racemic oxaziridine 18 in quantitative yield, which is also obtained from the imine 19 in a very fast reaction.The acid 16 effects slow decomposition of (R,S)-4-into carbon monoxide and imine 19, probably by general acid catalysis.The stereochemical result obtained from (R)-4 as well as the reaction conditions and differences in rate for formation and epoxidation of 19 suggest that in the peracid oxidation of an aziridinone the sequence of events consists of a rate-limiting, acid-catalysed decomposition into carbon monoxide and an imine, followed by very fast epoxidation of the latter.The previous mechanism, invoking as intermediates alleged aziridinone N-oxides, e.g. 17, is not supported by the present study. Key Words: Aziridinones, chiral, non-racemic / α-Lactams / Butanoic acids, 2-substituted 3,3-dimethyl- and derivatives / Perbenzoic acid, 3-chloro- / Oxaziridines / Cycloreversion Acid catalysis, general / Ethanol, (R)-1-(9-anthryl)-2,2,2-trifluoro- / Circular dichroism