Synthesis and Application of Substituted 1,16-Dihydroxytetraphenylenes in Catalytic Asymmetric Allylboration of Ketones

The synthesis and
application of a newly designed C2-symmetric
chiral-substituted 1,16-dihedroxytetraphenylene
(DHTP) is reported. Efficient syntheses of enantiopure substituted
DHTP were accomplished, and these enantiopure compounds were used
as organocatalysts in asymmetric allylboration of ketones under very
mild conditions. Accordingly, several tertiary alcohols were generated
in moderate to good yields with up to 99% ee by using the catalyst
(S)-2,15-Br2-DHTP. A gram-scale reaction
was achieved in 99% yield with 96% ee.