Enantioselective Synthesis of Phthalides and Isochromanones via Heck-Matsuda Arylation of Dihydrofurans.

In this communication, the enantioselective synthesis of phthalides and isochromanones is described through a new palladium-catalyzed Heck-Matsuda arylation/NaBH4 -reduction/lactonization sequence of 2,3- and 2,5-dihydrofurans in good overall yields and excellent enantioselectivities (up to 98:2 er). This expeditious synthesis of chiral Heck lactol intermediates allowed the diversification of the strategy to obtain medicinally relevant chiral lactones, amines, and olefins. The natural product 3-butylphthalide was obtained in three steps with an overall yield of 33 % yield in 98:2 er.