‘Three-Component Reaction’ with aromatic thioketones, phenyl azide, and dimethyl fumarate

✍ Scribed by Grzegorz Mlostoń; Jaroslaw Romański; Anthony Linden; Heinz Heimgartner

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: German
• Weight: 503 KB
• Volume: 80
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19970800617

✦ Synopsis

Abstract

The reaction of thiobenzophenone (= diphenylmethanethione; 8a) or 9__H__‐fluorene‐9‐thione (8b) and methyl fumarate (9) in excess PhN~3~ at 80° yields a mixture of diastereoisomeric thiiranes 10 and 11 (Scheme 1). A mechanism involving the initial formation of 1‐phenyl‐4, 5‐dihydro‐1__H__‐1, 2, 3‐triazole‐4, 5‐dicarboxylate 12 by 1, 3‐dipolar cycloaddition of PhN~3~ and 9 is proposed in Scheme 2. The diazo compound 13, which is in equilibrium with 12, undergoes a further 1, 3‐dipolar cycloaddition with thioketones 8 to give 2, 5‐dihydro‐1, 3, 4‐thiadiazoles 14. Elimination of N~2~ yields the thiocarbonyl ylide 15 which cyclizes to the corresponding thiirane. Desulfurization of the thiiranes 10 and 11 with hexamethylphosphorous triamide leads to the olefinic compounds 16 (Scheme 3). The crystal structures of 10a, 11a, and 16b were determined.