Mechanochemical synthesis of unsymmetrical salens for the preparation of Co–salen complexes and their evaluation as catalysts for the synthesis of α-aryloxy alcohols via asymmetric phenolic kinetic resolution of terminal epoxides

• Shengli Zuo,
• Shuxiang Zheng,
• Jianjun Liu and
• Ang Zuo

Beilstein J. Org. Chem. 2022, 18, 1416–1423, doi:10.3762/bjoc.18.147

• as an enantioselective catalyst for the asymmetric ring opening of terminal epoxides by phenols. A library of α-aryloxy alcohols 3 was thereafter synthesized in good yield and high ee using 2f via the phenolic KR of epichlorohydrin. Keywords: α-aryloxy alcohols; chiral Co–salen; HKR

• ; mechanochemistry; phenolic KR; Introduction In the past decade, more than twenty chiral small molecule drugs were approved by the FDA, including ruxolitinib, afatinib, sonidegib, encorafenib, lorlatinib, darolutamide, alpelisib, artesunate, maribavir, ponesimod, daridorexant and others [1][2][3]. The

• ]. Jones et al. designed a cyclooctene-based Co–salen macrocycle catalyst for the phenolic KR of epichlorohydrin and 1,2-epoxyhexane [21]. However, these Co–salen systems suffer from several limitations such as tedious preparation of salen scaffolds, excess use of epoxides, high catalyst loadings, narrow