CAS Key Laboratory of Science and Technology on Applied Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China.
State Key Laboratory of Chemical Resource Engineering, Institute of Computational Chemistry, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, China.
Nat Commun. 2022 Jun 11;13(1):3365. doi: 10.1038/s41467-022-30815-5.
Heteroatom-participated lignin depolymerization for heterocyclic aromatic compounds production is of great importance to expanding the product portfolio and meeting value-added biorefinery demand, but it is also particularly challenging. In this work, the synthesis of pyrimidines from lignin β-O-4 model compounds, the most abundant segment in lignin, mediated by NaOH through a one-pot multi-component cascade reaction is reported. Mechanism study suggests that the transformation starts by NaOH-induced deprotonation of Cα-H bond in β-O-4 model compounds, and involves highly coupled sequential cleavage of C-O bonds, alcohol dehydrogenation, aldol condensation, and dehydrogenative aromatization. This strategy features transition-metal free catalysis, a sustainable universal approach, no need of external oxidant/reductant, and an efficient one-pot process, thus providing an unprecedented opportunity for N-containing aromatic heterocyclic compounds synthesis from biorenewable feedstock. With this protocol, an important marine alkaloid meridianin derivative can be synthesized, emphasizing the application feasibility in pharmaceutical synthesis.
杂原子参与的木质素解聚对于生产杂环芳烃化合物具有重要意义，可以扩大产品组合并满足增值生物炼制的需求，但这也极具挑战性。在这项工作中，报道了通过一锅多组分级联反应，在 NaOH 介导下，从木质素β-O-4 模型化合物（木质素中最丰富的片段）合成嘧啶。通过机理研究表明，该转化首先由 NaOH 诱导β-O-4 模型化合物中 Cα-H 键的去质子化，然后涉及高度耦合的 C-O 键连续断裂、醇脱氢、醛醇缩合和脱氢芳构化。该策略的特点是无过渡金属催化、可持续的通用方法、无需外加氧化剂/还原剂以及高效的一锅法工艺，从而为从生物可再生原料合成含氮芳杂环化合物提供了前所未有的机会。利用该方案可以合成重要的海洋生物碱 meridianin 衍生物，强调了其在药物合成中的应用可行性。
