Structure of pyrrolisidinediones ? Products of the intramolecular cyclization of aminoketo-stabilized sulfonium ylides
摘要:
The structure of three pyrrolisidinediones was determined by x-ray crystallographic analysis. A pseudocentrosymmetrical structure of the dimer crystal with a molecule of water of crystallization close to the inversion center was detected in the oxidation product.
transformations of phthalimido-substituted keto-stabilized sulfoniumylides, including optically active ylides, were studied. The thermolysis of sulfoniumylides obtained from α- and β-amino acids leads to methylthio-substituted pyrrolizidine- and indolizidinediones. Racemization of optically active ylides does not occur. Sulfoniumylides with longer carbon chains do not undergo intramolecular cyclization