Synthesis of 3‐(ω‐Hydroxyalkoxy)isobenzofuran‐1(3H)‐ones by Trifluoroacetic Acid‐Mediated Lactonization of tert‐Butyl 2‐(1,3‐Dioxol‐2‐yl)‐ or 2‐(1,3‐Dioxan‐2‐yl)benzoates |
| |
| Authors: | Kazuhiro Kobayashi Minami Kuroda |
| |
| Institution: | Division of Applied Chemistry, Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4‐101 Koyama‐minami, Tottori 680‐8552, Japan() |
| |
| Abstract: | An efficient two‐step method for the preparation of 3‐(2‐hydroxyethoxy)‐ or 3‐(3‐hydroxypropoxy)isobenzofuran‐1(3H)‐ones 3 has been developed. Thus, the reaction of 1‐(1,3‐dioxol‐2‐yl)‐ or 1‐(1,3‐dioxan‐2‐yl)‐2‐lithiobenzenes, generated in situ by the treatment of 1‐bromo‐2‐(1,3‐dioxol‐2‐yl)‐ or 1‐bromo‐2‐(1,3‐dioxan‐2‐yl)benzenes 1 with BuLi in THF at ?78°, with (Boc)2O afforded tert‐butyl 2‐(1,3‐dioxol‐2‐yl)‐ or 2‐(1,3‐dioxan‐2‐yl)benzoates 2 , which can subsequently undergo facile lactonization on treatment with CF3COOH (TFA) in CH2Cl2 at 0° to give the desired products in reasonable yields. |
| |
| Keywords: | Isobenzofuran‐1(3H)‐ones 3‐(ω ‐hydroxyalkoxy)‐ Acetic acid 2 2 2‐trifluoro‐ Lactonization Br/Li Exchange tert‐Butoxycarbonylation |
|
|
