The reaction of N-aryl nitrones with dichloroketene: A new synthesis of isatins

Rearrangement of N-Oxyenamines and Related Reactions

“…It should also be noted that nitrones, which are incapable of achieving the conformation required for cycloaddition or rearrangement (i.e., 169 ), follow other reaction pathways . Dichloroketene after hydrolysis leads to the isatins 170 . Besides ketenes, the reaction is also applicable to ketenimines, although in this case oxindole formation might follow a non-[3,3]-rearrangement pathway. , …”

“…130 Dichloroketene after hydrolysis leads to the isatins 170. 135 Besides ketenes, the reaction is also applicable to ketenimines, 136 although in this case oxindole formation might follow a non-[3,3]-rearrangement pathway. 136a,b The [3 + 2]-adducts of nitrones and acetylenes can undergo various transformations depending on the reaction conditions and substrate structure.…”

Ketene. Part 23. Conformational control of the addition reactions of ketenes with N-phenylnitrones

“…(Found: C, 85.4; H, 6.0; N, 2.7. C36H29N02 requires C, 85.2; H, 5.7; N, 2.8%); v,,,~(CHCl,) m), 6.7-6.9 (2 H, m), and 7.1-7.7 (19 H, m); m/z 507 (M', Ox), 463 (23), 462 (31), 447 (37), 386 (9,370 (20), 355 (7) oxidised with yellow mercuric oxide (10 g) anhydrous sodium sulphate (2 g), and Celite (5 g) in dry ether (150 ml) with ethanolic potassium hydroxide as described above for (5c). The resulting purple solution was filtered and evaporated under reduced pressure to ca.…”