The use of Lewis acids as catalysts is one of the most powerful strategies in organic chemistry.[1] In general, conventional Lewis acids such as AlCl3, TiCl4, BF3· OEt2, SnCl4, etc., require strictly anhydrous conditions because they immediately react with water in preference to the substrates, resulting in serious decomposition of the catalysts or the substrates. To address this issue, water-compatible Lewis acid catalyzed organic ...