Synthesis of Bis-BINOL Derivatives: Linking via the 3-, 4-, or 5-Position by Generation of Suitable C 1-Symmetric Precursors

Bis-BINOL derivatives have proven highly useful in applications such as chemosensing or organocatalysis. In this account, we describe strategies for the linking of BINOL units via the 3-, 4-, or 5-positions, showing that unique synthetic strategies are necessary to address each position. We report the synthesis of suitable C 1-symmetric precursors, which are generated either by monohalogenation or by monodeprotection of C 2-symmetric starting materials, and their subsequent coupling to give linked bis-BINOL derivatives.