Catalytic asymmetric synthesis with rh-diene complexes: 1,4-addition of arylboronic acids to unsaturated esters.
A general route to enantioenriched tert-butyl 3,3-diarylpropanoates is presented. These useful building blocks are prepared via an asymmetric rhodium-catalyzed conjugate addition of arylboronic acids to unsaturated tert-butyl esters in the presence of chiral dienes as ligands. The addition of both electron-poor and electron-rich boronic acids proceeds smoothly with various enoates in 63-90% yield with high enantioselectivites (89-94% ee). [reaction: see text]
Paquin
Jean-François
JF
Laboratorium für Organische Chemie, ETH Hönggerberg, HCI H335, 8093 Zürich, Switzerland.
Stephenson
Corey R J
CR
Defieber
Christian
C
Carreira
Erick M
EM