A highly efficient, catalytic strategy for the deprotection of classical phenacyl (Pac) as well as desyl (Dsy) protection groups has been developed using visible light photoredox catalysis. The deliberate use of a neutral two-phase acetonitrile/water mixture with K₃PO₄ applying catalytic amounts of [Ru(bpy)₃](PF₆)₂ in combination with ascorbic acid is the key to this truly catalytic deprotection of Pac- and Dsy-protected carboxylic acids. Our mild yet robust protocol allows for fast and selective liberation of the free carboxylic acids in very good to quantitative yields, while only low catalyst loadings (1 mol %) are required. Both Pac and Dsy, easily introduced from commercially available precursors, can be applied for the direct protection of carboxylic acids and amino acids, offering orthogonality to a great variety of other common protecting groups. We further demonstrate the general applicability and versatility of these formerly underrated protecting groups in combination with our catalytic cleavage conditions, as underscored by the gained high functional group tolerance. Moreover, this method could successfully be adapted to the requirements of solid-phase synthesis. As a proof of principle for an efficient visible light, photocatalytic linker cleavage, a Boc-protected tripeptide was split off from commercially available brominated Wang resin.

中文翻译：

---

Desyl和Phenacyl作为多功能，光催化可裂解的保护基团：在不同（可见）光下的经典方法

已经开发了使用可见光光氧化还原催化来脱保护经典苯甲酰基（Pac）和去甲酰基（Dsy）保护基的高效催化策略。故意使用具有K ₃ PO ₄的中性两相乙腈/水混合物，并施加催化量的[Ru（bpy）₃ ]（PF ₆）₂与抗坏血酸结合使用是对Pac和Dsy保护的羧酸进行真正的催化脱保护的关键。我们温和而稳健的方案允许以非常好的定量产量快速而选择性地释放游离羧酸，而只需要低的催化剂负载量（1 mol％）。从市场上可买到的前体容易引入的Pac和Dsy均可用于直接保护羧酸和氨基酸，与许多其他常见的保护基团具有正交性。我们进一步证明了这些先前被低估的保护基团与我们的催化裂解条件相结合的普遍适用性和多功能性，这是由获得的高官能团耐受性所强调的。而且，该方法可以成功地适应固相合成的要求。作为有效可见光，光催化连接子裂解的原理证明，将Boc保护的三肽从市售的溴化王树脂中分离出来。