Rhodium-catalyzed asymmetric 1, 4-addition of arylboronic acids to coumarins proceeded with high enantioselectivity in the presence of a rhodium catalyst (3 mol%) generated from Rh (acac)(C2H4) 2 and (R)-Segphos to give the corresponding (R)-4-arylchroman-2-ones in over 99% ee. This asymmetric reaction was applied to the synthesis of (R)-tolterodine.
