Enantioselective Total Synthesis of Chromanone Lactone Homo‐ and Heterodimers

A one pot borylation/Suzuki–Miyaura reaction of the 4‐bromochromanone lactones 21 and 23 , respectively, followed by cleavage of the methyl ether moieties gave the homodimeric chromanone lactones 10 and 11 . Reaction of a 1:1 mixture of 21 and 23 under otherwise identical conditions gave a 1:1:2‐mixture of the two homodimers 10 and 11 and the heterodimer 12 . This is the first example of the preparation of a heterodimeric chromanone lactone. For the enantioselective synthesis of the starting material, phenol 17 was transformed into the chromane 18 using a Wacker‐type cyclisation with 99 % ee and 80 % yield.