Synthesis of 7,7′-Dihydroxy-8,8′-biquinolyl (azaBINOL) via Pd-catalyzed directed double C-H functionalization of 8,8′-biquinolyl: Emergence of an atropos from a tropos state

摘要

7,7′-Dihydroxy-8,8′-biquinolyl (azaBINOL) was prepared from 2-chloroaniline in four steps: (1) the Skraup reaction, (2) Ni-catalyzed reductive coupling of 8-chloroquinoline, (3) Pd(II)-catalyzed double C-H functionalization of 8,8′-biquinolyl mediated by PhI(OAc)_2, and (4) saponification. During the third step, an axially chiral (atropos type) biaryl molecule was directly generated from an essentially achiral (tropos type) biaryl starting material.