Integrating benzofuran and heteroradialene into donor-acceptor covalent organic frameworks for photocatalytic construction of multi-substituted olefins

• Published in: Applied catalysis. B, Environmental Environmental, 2022-11, Vol.316, p.121630, Article 121630
• Main Authors: An, Wan-Kai, Zheng, Shi-Jia, Xu, Xin, Liu, Li-Jie, Ren, Jia-Sen, Fan, Liangxin, Yang, Zhan-Kun, Ren, Yunlai, Xu, Cuilian
• Format: Article
• Language: English
• Subjects: Benzofuran; Covalent organic frameworks; Multi-substituted olefins; Photocatalysis
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2022.121630

Covalent organic framework (COF) is a novel platform to develop efficient and green safe heterogeneous photocatalysts. Additionally, multiple photoredox reactions and mechanism studies over porous catalysts remain to be further exploited. In this context, two benzofuran-embedded COFs (BF-COFs) with favorable solvent tolerance were constructed via tautomerism strategy. Attributing to the benzofuran-hetero[6]radialene knots, BF-COFs displayed as donor-acceptor properties, and exhibited wide visible light response range and well separation efficiency for photogenerated charges. Under visible-light, BF-COFs could promote the C-S bond formation reaction between β-ketoate ester and its analogues with NH4SCN, affording multi-substituted olefins (28 examples, upto 98% yield) efficiently. Moreover, the atomic economic strategy was also applicative to prepare L-proline derived olefins (≥ 99% ee), which could be further converted into the chiral amino-substituted thiazoles (99% yield and ≥ 99% ee). The research about BF-COFs sheds light on the green construction of C-S bond, (chiral) olefins and chiral amino thiazoles. [Display omitted] •Two benzofuran-heteroradialene joints-embedded BF-COFs were facilely constructed and proved to be donor-acceptor structures.•BF-COFs exhibit remarkable photocatalytic activity for the synthesis of multi-substituted olefins with upto 98% yield (28 examples).•BF-COFs can promote the synthesis of L-proline-derived olefins and amino-substituted thiazoles with maintained chirality (≥ 99% ee).•The photocatalytic mechanism for multi-substituted olefins synthesis were elaborated in detail.