One-pot synthesis of 4,5,6-triacetoxyisoindole-1,3‑dione derivatives by hydride transferring agent in Ac2O: Explanation of the regioselectivity in the molecule by theoretical calculations

Isoindole-1,3‑dione derivatives containing an epoxy alcohol unit were synthesized. Epoxy alcohols were converted to the corresponding 1,2,3-triacetate derivatives in a one-pot manner using the NaBH4/Ac20 system for the first time and in high yield. C-3 selective ring-opening products were obtained with good yield and with stereospecificity with the NaBH4/Ac2O system at 139–140 °C. The exact configuration of 2-methyl-1,3-dioxooctahydro-1H-isoindole-4,5,6-triyltriacetate was determined by X-ray diffraction analysis which was obtained from the reaction of epoxy alcohol by hydride transferring agent in acetic anhydride. On the other hand, theoretical computations were carried out to explain the regioselectivity in the ring opening reaction of epoxy alcohols. The results showed that the ring-opening reaction of epoxy alcohol proceeds in a thermodynamically controlled manner and regioselectivity occurs depending on the stability of the products.