Herrera-Luna Jorge C, Díaz David Díaz, Jiménez M Consuelo, Pérez-Ruiz Raúl
Departamento de Química, Universitat Politècnica de València (UPV), Camino de Vera S/N, 46022 Valencia, Spain.
Departamento de Química Orgánica and Instituto de Bio-Orgánica Antonio González, Universidad de La Laguna, Avda. Astrofísico Francisco Sánchez 3, 38206 La Laguna, Spain.
ACS Appl Mater Interfaces. 2021 Oct 20;13(41):48784-48794. doi: 10.1021/acsami.1c14497. Epub 2021 Oct 7.
A new strategy to achieve efficient aerobic phosphorylation of five-membered heteraroenes with excellent yields using dichromatic photoredox catalysis in a gel-based nanoreactor is described here. The procedure involves visible aerobic irradiation (cold white LEDs) of a mixture containing the heteroarene halide, trisubstituted phospite, ,-diisopropylethylamine (DIPEA) as sacrificial agent, and catalytic amounts of 9,10-dicyanoanthracene () in the presence of an adequate gelator, which permits a faster process than at the homogeneous phase. The methodology, which operates by a consecutive photoinduced electron transfer (ConPET) mechanism, has been successfully applied to the straightforward and clean synthesis of a number of different heteroarene (furan, thiophene, selenophene, pyrrole, oxazole, or thioxazole) phosphonates, extending to the late-stage phosphonylation of the anticoagulant rivaroxaban. Strategically, employment of cold white light is critical since it provides both selective wavelengths for exciting first (blue region) and subsequently its corresponding radical anion (green region). The resultant strongly reducing excited agent * is capable of even activate five-membered heteroarene halides (Br, Cl) with high reduction potentials (∼-2.7 V) to effect the C(sp)-P bond formation. Spectroscopic and thermodynamic studies have supported the proposed reaction mechanism. Interestingly, the rate of product formation has been clearly enhanced in gel media because reactants can be presumably localized not only in the solvent pools but also through to the fibers of the viscoelastic gel network. This has been confirmed by field-emission scanning electron microscopy images where a marked densification of the network has been observed, modifying its fibrillary morphology. Finally, rheological measurements have shown the resistance of the gel network to the incorporation of the reactants and the formation of the desired products.
本文描述了一种在基于凝胶的纳米反应器中使用双色光氧化还原催化实现五元杂芳烃高效需氧磷酸化并获得优异产率的新策略。该过程包括在适当的凝胶剂存在下，对含有杂芳烃卤化物、三取代亚磷酸酯、作为牺牲剂的N,N-二异丙基乙胺（DIPEA）和催化量的9,10-二氰基蒽（DCA）的混合物进行可见光需氧照射（冷白色发光二极管），这使得该过程比均相阶段更快。该方法通过连续光诱导电子转移（ConPET）机制运行，已成功应用于多种不同杂芳烃（呋喃、噻吩、硒吩、吡咯、恶唑或噻恶唑）膦酸酯的直接且清洁的合成，还扩展到抗凝血剂利伐沙班的后期膦酰化。从策略上讲，使用冷白光至关重要，因为它提供了用于首先激发DCA（蓝色区域）及其相应自由基阴离子（绿色区域）的选择性波长。产生的强还原性激发剂DCA*甚至能够活化具有高还原电位（约-2.7 V）的五元杂芳烃卤化物（Br、Cl）以实现C(sp)-P键的形成。光谱和热力学研究支持了所提出的反应机理。有趣的是，在凝胶介质中产物形成的速率明显提高，因为反应物可能不仅定位在溶剂池中，还贯穿到粘弹性凝胶网络的纤维中。场发射扫描电子显微镜图像证实了这一点，其中观察到网络有明显的致密化，改变了其纤维形态。最后，流变学测量表明凝胶网络对反应物掺入和所需产物形成的阻力。
