Abstract：
Lignocellulose is mainly composed of hydrophobic lignin and hydrophilic polysaccharide polymers, contributing to an indispensable carbon resource for green biorefineries1,2. When chemically treated, lignin is compromised owing to detrimental intra- and intermolecular crosslinking that hampers downstream process3,4. The current valorization paradigms aim to avoid the formation of new C-C bonds, referred to as condensation, by blocking or stabilizing the vulnerable moieties of lignin5-7. Although there have been efforts to enhance biomass utilization through the incorporation of phenolic additives8,9, exploiting lignin\'s proclivity towards condensation remains unproven for valorizing both lignin and carbohydrates to high-value products. Here we leverage the proclivity by directing the C-C bond formation in a catalytic arylation pathway using lignin-derived phenols with high nucleophilicity. The selectively condensed lignin, isolated in near-quantitative yields while preserving its prominent cleavable β-ether units, can be unlocked in a tandem catalytic process involving aryl migration and transfer hydrogenation. Lignin in wood is thereby converted to benign bisphenols (34-48 wt%) that represent performance-advantaged replacements for their fossil-based counterparts. Delignified pulp from cellulose and xylose from xylan are co-produced for textile fibres and renewable chemicals. This condensation-driven strategy represents a key advancement complementary to other promising monophenol-oriented approaches targeting valuable platform chemicals and materials, thereby contributing to holistic biomass valorization.
摘要：
木质纤维素主要由疏水性木质素和亲水性多糖聚合物组成，为绿色生物炼油厂提供不可或缺的碳源1,2。经过化学处理,木质素由于有害的分子内和分子间交联而受到损害，这阻碍了下游过程3,4。当前的价值化范式旨在避免形成新的C-C键，被称为冷凝，通过阻断或稳定木质素5-7的脆弱部分。尽管一直在努力通过掺入酚类添加剂8,9来提高生物质的利用率，但利用木质素的缩合倾向仍未被证实可以使木质素和碳水化合物增值为高价值产品。在这里,我们通过使用具有高亲核性的木质素衍生的酚在催化芳基化途径中引导C-C键形成来利用倾向性。选择性浓缩的木质素，以接近定量的产量分离，同时保留其突出的可裂解β-醚单元，可以在涉及芳基迁移和转移氢化的串联催化过程中解锁。木材中的木质素由此转化为良性双酚(34-48重量%),其代表其基于化石的对应物的性能有利的替代品。来自纤维素的脱木素纸浆和来自木聚糖的木糖共同生产用于纺织纤维和可再生化学品。这种冷凝驱动的策略代表了一个关键的进步，以其他有前途的单酚为导向的方法针对有价值的平台化学品和材料，从而有助于整体生物量的增值。
