Singh A, Fennell C J, Weaver J D
Department of Chemistry , Oklahoma State University , Stillwater , OK 74078 , USA . Email:
Chem Sci. 2016 Nov 18;7(11):6796-6802. doi: 10.1039/c6sc02422j. Epub 2016 Jul 21.
Photocatalytic alkene synthesis can involve electron and energy transfer processes. The structure of the photocatalyst can be used to control the rate of the energy transfer, providing a mechanistic handle over the two processes. Jointly considering catalyst volume and emissive energy provides a highly sensitive strategy for predicting which mechanistic pathway will dominate. This model was developed to a photocatalytic C-F alkenylation reaction of alkynes and highly-fluorinated arenes as partners. By judicious choice of photocatalyst, access to - or -olefins was accomplished, even in the case of synthetically challenging trisubstituted alkenes. The generality and transferability of this model was tested by evaluating established photocatalytic reactions, resulting in shortened reaction times and access to complimentary -cinnamylamines in the photocatalytic [2 + 2] and C-H vinylation of amines, respectively. These results show that taking into account the size of the photocatalyst provides predictive ability and control in photochemical quenching events.
光催化烯烃合成可涉及电子和能量转移过程。光催化剂的结构可用于控制能量转移速率，从而为这两个过程提供一种机理控制手段。综合考虑催化剂体积和发射能量为预测哪种机理途径将占主导地位提供了一种高度灵敏的策略。该模型被应用于炔烃与高度氟化芳烃作为反应物的光催化C-F烯基化反应。通过明智地选择光催化剂，即使在合成具有挑战性的三取代烯烃的情况下，也能实现生成反式或顺式烯烃。通过评估已有的光催化反应来测试该模型的通用性和可转移性，分别在光催化[2 + 2]反应和胺的C-H乙烯基化反应中缩短了反应时间并得到了互补的反式肉桂胺。这些结果表明，考虑光催化剂的大小可在光化学猝灭事件中提供预测能力和控制能力。
