Over the past three decades, triflate salts have emerged as crucial Lewis acid catalysts in organic synthesis, playing a significant role in cyclization, C-H bond functionalization, and various other reactions. Among these, rare-earth triflates have garnered attention due to their water compatibility, environmental friendliness, noncorrosive nature, and reusability. In particular, scandium(III) triflate [Sc(OTf)3] stands out as a water-resistant Lewis acid with remarkable catalytic activity in aqueous environments. Unlike typical Lewis acids such as AlCl3, BF3, and SnCl4, which are decomposed or deactivated by water, Sc(OTf)3 remains stable and effective. Its exceptional Lewis acidity, resilience against hydrolysis, and recyclability make it a prominent green catalyst. The unique stability of Sc(OTf)3 in water is attributed to the smaller size of scandium ions (Sc3+), enhancing its catalytic efficiency. Sc(OTf)3 has a longstanding history in organic synthesis, facilitating a wide range of reactions including aldol, Michael, allylation, Friedel-Crafts acylations, Diels-Alder, Mannich, cycloadditions (including cyclopropanation), and cascade reactions. The increasing utilization of Sc(OTf)3 over the past decade underscores the necessity for updated insights. This review provides a concise overview of the versatility of Sc(OTf)3 as a catalyst, focusing on developments from 2017 to 2024.

中文翻译：

---

三氟甲磺酸钪(III)催化的最新进展：综述


在过去的三十年中，三氟甲磺酸盐已成为有机合成中关键的路易斯酸催化剂，在环化、CH键官能化和各种其他反应中发挥着重要作用。其中，稀土三氟甲磺酸盐由于其水相容性、环境友好性、无腐蚀性和可重复使用性而受到关注。特别是，三氟甲磺酸钪(III) [Sc(OTf)3]作为一种防水路易斯酸脱颖而出，在水性环境中具有显着的催化活性。与 AlCl3、BF3 和 SnCl4 等典型路易斯酸会被水分解或失活不同，Sc(OTf)3 保持稳定且有效。其卓越的路易斯酸度、抗水解能力和可回收性使其成为杰出的绿色催化剂。 Sc(OTf)3 在水中的独特稳定性归因于钪离子 (Sc3+) 的尺寸较小，从而提高了其催化效率。 Sc(OTf)3 在有机合成领域有着悠久的历史，可促进多种反应，包括羟醛反应、Michael 反应、烯丙基化反应、Friedel-Crafts 酰化反应、Diels-Alder 反应、Mannich 反应、环加成反应（包括环丙烷化反应）和级联反应。过去十年中 Sc(OTf)3 的利用率不断增加，强调了更新见解的必要性。本综述简要概述了 Sc(OTf)3 作为催化剂的多功能性，重点关注 2017 年至 2024 年的发展。