1.
Org Biomol Chem
; 17(27): 6551-6556, 2019 07 21.
Artículo
en Inglés
| MEDLINE
| ID: mdl-31225578
RESUMEN
A novel methodology toward the diversity-oriented asymmetric construction of densely functionalized isoxazole-dispirobisoxindoles was developed. This approach is distinguished by an organocatalytic stereo- and appealing ß-regioselective [3 + 2] cycloaddition reaction of 3-methyl-4-nitro-5-isatylidenyl-isoxazoles and 3-isothiocyanato oxindoles. Complex polycyclic oxindoles 3 featuring two different oxindole moieties and three contiguous stereocenters were smoothly afforded in up to 96% yield, 96% ee, and >20 : 1 dr. The described method, which is different from our previous work of α-regioselective asymmetric annulation of 3-methyl-4-nitro-5-isatylidenyl-isoxazoles, is the first ß-regioselective asymmetric annulation.