| Abstract
| - A novel method for the synthesis of phthalides and 3,4-dihydroisocoumarins via the palladium-catalyzed intramolecular benzannulation of bis-enyne and enyne−diyne systems is described.Various kinds of substituted phthalides 9 and 17 and 3,4-dihydroisocoumarins 19 were synthesizedfrom 8, 16, and 18, respectively, in moderate to excellent yields. The benzannulation reactionproceeded chemoselectively to give the corresponding fused ring compounds A without the formationof the regioisomeric products B (eq 6). Furthermore, this methodology was applied to the synthesisof biologically active 3-n-butylphthalide 23.
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