Hydroiodination-Triggered Cascade Reaction with I2/PPh3/H2O: Metal-Free Access to 3-Substituted Phthalides from 2-Alkynylbenzoates

Phthalide is an important scaffold found in several biologically active compounds. Therefore, effective methods for the synthesis of phthalides are strongly desired. Herein, we describe the metal-free synthesis of 3-substituted phthalides by the reductive hydroiodination of 2-alkynylbenzoates through an I-2/PPh3/H2O-triggered cascade reaction. A variety of 3-substituted phthalides were synthesized in excellent yields by a onepot reaction involving four processes: desilylation, hydroiodination, cyclization, and reduction.