Ruthenium(II)-Catalyzed C–H Annulation of Mandelic Acids with Internal Alkynes to Construct Isocoumarins.

Keywords: ruthenium catalysis; mandelic acids; alkynes; annulation; isocoumarins EN ruthenium catalysis mandelic acids alkynes annulation isocoumarins 2005 2010 6 10/09/23 20231024 NES 231024 Graph Isocoumarins are an important class of natural lactones, and their skeletal structure is an important part of many active pharmaceutical ingredients. At present, the major methods for synthesizing isocoumarins include (1) the cyclization reaction of I ortho i -halogen-substituted benzoic acids or their esters or amides with 1,3-diketones or internal alkynes; [10][11][12] and (2) the internal cyclization reaction of I ortho i -alkenyl- or alkynyl-substituted benzoic acids or their esters. The reactions of benzaldehydes B 5 b and benzoic acids B 6 b with B 2a b proceeded when the amount of Cu(OAc) SB 2 sb -H SB 2 sb O was increased to 1.5 equivalents and the reaction time was shortened to ten hours. Ruthenium(II)-Catalyzed C-H Annulation of Mandelic Acids with Internal Alkynes to Construct Isocoumarins. [Extracted from the article]