Abstract
The first catalytic asymmetric total synthesis of (+)-propolisbenzofuran
B, enabled by a highly enantioselective rhodium-catalyzed hy-drogenation
of a tetrasubstituted olefin, was described. Other noteworthy aspects
include the construction of the central hydrodiben-zo[b,d]furan core
through a sequence of Zn(II)-mediated regioselective benzofuran
formation and Dieckmann condensation, as well as C-H oxidations,
involving a visible light-induced Fe(III)-catalyzed benzylic C(sp3)-H
oxidation. Additionally, the absolute configuration was confirmed by
X-ray analysis of a carbonate intermediate.