Glycidic esters represent pivotal constituents in synthetic chemistry, offering enhanced versatility for tailoring toward a diverse array of molecular targets in comparison with simple epoxides. While considerable progress has been made in the asymmetric synthesis of trans- and trisubstituted glycidic esters, achieving enantioselective preparation of cis-glycidic esters has remained a long-standing challenge. Here, we demonstrate a selectivity-predictable modular platform for the asymmetric synthesis of cis-glycidic esters via a novel dinuclear (salen)titanium(III)-catalyzed radical-type kinetic resolution (KR) approach. This radical KR protocol operates under mild conditions and demonstrates a wide substrate scope, facilitating the synthesis of alkyl- and aryl-substituted cis-glycidic esters with high levels of regioselectivity and enantioselectivity, along with hydroxy ester byproducts representing synthetically valuable motifs as well. This study presents a unique exploration of radical-type KR applied to epoxides, effectively overcoming the steric challenges inherent in conventional nucleophilic-type methodologies typically employed in epoxide chemistry.

中文翻译：

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双核钛(III)催化环氧化物的自由基型动力学拆分用于顺式缩水甘油酯的对映选择性合成

缩水甘油酯是合成化学中的关键成分，与简单的环氧化物相比，缩水甘油酯具有增强的多功能性，可针对多种分子靶标进行定制。虽然反式和三取代缩水甘油酯的不对称合成已经取得了相当大的进展，但实现顺式缩水甘油酯的对映选择性制备仍然是一个长期存在的挑战。在这里，我们展示了一种选择性可预测的模块化平台，用于通过新型双核（salen）钛（III）催化的自由基型动力学拆分（KR）方法不对称合成顺式缩水甘油酯。这种自由基 KR 方案在温和条件下运行，并表现出广泛的底物范围，促进具有高水平区域选择性和对映选择性的烷基和芳基取代的顺式缩水甘油酯的合成，以及代表具有合成价值的基序的羟基酯副产物。这项研究对应用于环氧化物的自由基型 KR 进行了独特的探索，有效克服了环氧化物化学中通常采用的传统亲核型方法所固有的空间挑战。