The synthesis of tris(ortho-carboranyl)borane (BoCb3), a single site neutral Lewis superacid, in one pot from commercially available materials is achieved. The high fluoride ion affinity (FIA) confirms its classification as a Lewis superacid and the Gutmann-Beckett method as well as adducts with Lewis bases indicate stronger Lewis acidity over the widely used fluorinated aryl boranes. The electron withdrawing effect of ortho-carborane and lack of pi-delocalization of the LUMO rationalize the unusually high Lewis acidity. Catalytic studies indicate that BoCb3 is a superior catalyst for promoting C−F bond functionalization reactions than tris(pentafluorophenyl)borane [B(C6F5)3].
Funding
Baylor University, the Welch Foundation (Grant No. AA-1846), the National Science Foundation (Award No. 1753025), and the Australian Research Council (FT16010007, DP20010013).