AbstractCopper‐catalyzed coupling reaction of 2‐iodobenzoic acids and alkynes such as terminal acetylenes, alkynyl carboxylic acids, and trimethylsilylacetylene selectively afforded isocoumarins and phthalides in the presence of cesium carbonate (Cs2CO3) and dimethyl sulfoxide (DMSO). Among the regioselective products, only the 6‐endo‐dig product, isocoumarin, was formed at 100 °C, and the 5‐exo‐dig product, phthalide, was formed as a major product at 25 °C. A variety of alkynes produced the corresponding isocoumarins and phthalides in good yields. A mechanism is suggested in which the formation of 2‐alkynylbenzoic acid as an intermediate via Sonogashira‐type coupling was ruled out in the reaction pathway.magnified image
The first asymmetric hydrogenation of 3‐ylidenephthalides has been developed using the IrI complex of a spiro[4,4]‐1,6‐nonadiene‐based phosphine‐oxazoline ligand (SpinPHOX) as the catalyst, affording a wide variety of chiral 3‐substituted phthalides in excellent enantiomeric excesses (up to 98 % ee). The utility of the protocol has been demonstrated in the asymmetricsynthesis of chiral drugs NBP and