In this study, we found that the sterically bulky α‐hydroxycarboxamide moiety is a suitable framework for protecting the boronyl group of boron reagents during aminations. Condensation of α‐hydroxycarboxamide with ArB(OH)2 produced aryloxazaborolidinone (ArOxB). The reactivity of the C‐B bond in ArOxB is easily controlled by the steric and weak electronic effects of the backbone. H2N‐(or Br−)ArOxB underwent Chan‐Evans‐Lam (C‐E‐L) or Buchwald‐Hartwig (B‐H) amination with retaining the C−B bond. On the other hand, direct C‐E‐L amination of ArOxB was also possible in an oxidative atmosphere, in which the C−B bond was activated by CuII species. Our methodology is effective for the precise synthesis of two or more arylamino group substituted arenes.