Enantioselective Iridium‐Catalyzed Phthalide Formation through Internal Redox Allylation of Phthalaldehydes

Abstract

Red und Ox: Durch interne Redoxallylierung von o‐Phthalaldehyden wurden Phthalide enantioselektiv synthetisiert. Der insgesamt redoxneutrale Prozess umfasst eine oxidative Veresterung und eine reduktive Carbonyladdition, die sich gegenseitig ausgleichen. Die Methode ermöglichte formale Synthesen von ent‐Spirolaxin‐Methylether und CJ‐12,954.

Enantioselective Isoprenylboration Reaction of Aldehydes Catalyzed by a Chiral Phosphoric Acid

“…[17] Chiral isobenzofuranones (or called "phthalides") are important compounds possessing a broad range of biological activities, and the exploration of catalytic asymmetric approaches to the entities has drawn great interest. [18] Methyl 2-formylbenzoate 5 and boronate 2 underwent the initial asymmetric isoprenylboration at À 60°C for 40 h and sequential intramolecular transesterification at rt for 24 h to afford the desired enantioenriched isoprenyl-substituted phthalide 6 in 90% yield with 82.5:17.5 er. Furthermore, the synthetic utility of chiral adduct (R)-3 a through t BuO 2 H-mediated asymmetric epoxidation and Diels-Alder reactions was displayed, and chiral vinyloxirane 7 and cyclohexene 8 were prepared with good results, respectively (Scheme 3).…”

Ir‐SpinPHOX Catalyzed Enantioselective Hydrogenation of 3‐Ylidenephthalides

“…[7] Thea symmetric catalytic strategies developed for 3-substituted chiral phthalides were mostly based on the conversion of 2-acylarylcarboxylates into the enantioenriched 2-(hydroxymethyl) arylcarboxylates via asymmetric hydrogenation (AH), [8] transfer hydrogenation, [9] or organometallic addition, [10] followed by an in situ lactonization (Scheme 2a). Alternative asymmetric catalytic methods via dihydroxylation and lactonization, [11] ketone hydroacylation, [12] or redox allylation [13] have also been explored.…”