Keywords: Tris(pentafluorophenyl)borane / Diarylborinic acid / Arylboronic acid / Chiral arylboron catalyst / Lewis acid Arylboron compounds, Ar n B(OH) 3-n (n = 1-3), bearing merization, its potential as a Lewis acid catalyst for organic transformation is now much more extensive. Diarylborinic electron-withdrawing aromatic groups such as triarylboranes, diarylborinic acids, and arylboronic acids represent acids and arylboronic acids have shown themselves to be powerful tools in the design of chiral boron catalysts. This a new class of air-stable and water-tolerant Lewis acid or BrΓΈnsted acid catalysts in organic synthesis. In particular, article provides a comprehensive summary of the organic transformations catalyzed by arylboron compounds as acids. while tris(pentafluorophenyl)borane has primarily been used as a co-catalyst in metallocene-mediated olefin polythe presence of even a small amount of water causes rapid
1. Introduction decomposition or deactivation of the promoters. To obviate
The classical boron Lewis acids, BX 3 , RBX 2 , and R 2 BX some of these inherent problems, the potential of arylboron (X Ο F, Cl, Br, OTf) are now popular tools in organic syncompounds, Ar n B(OH) nΟͺ3 (n Ο 1Οͺ3), bearing electronthesis. In general, these are used stoichiometrically in orwithdrawing aromatic groups as a new class of boron cataganic transformations under anhydrous conditions, since lysts has been recently demonstrated (Figure 1). For example, tris(pentafluorophenyl)borane ( 1) is a convenient, commercially available Lewis acid of comparable strength [a] Research Center for Advanced Waste and Emission Manageto BF 3 , but without the problems associated with reactive ment, Nagoya University, BΟͺF bonds. Although its primary commercial application Furo-cho, Chikusa, Nagoya 464-8603, Japan is as a co-catalyst in metallocene-mediated olefin polymeri- [b] Graduate