Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, 44780, Bochum, Germany.
Angew Chem Int Ed Engl. 2017 Feb 6;56(7):1760-1764. doi: 10.1002/anie.201610179. Epub 2017 Jan 10.
Experiments in low-temperature matrices reveal that triplet diphenylcarbene inserts into the very strong B-F bond of BF in a two-step reaction. The first step is the formation of a strongly bound Lewis acid-base complex between the singlet state of diphenylcarbene and BF . This step involves an inversion of the spin state of the carbene from triplet to singlet. The second step requires visible-light photochemical activation to induce a 1,2-F migration from boron to the adjacent carbon atom under formation of the formal insertion product of the carbene center into BF . The 1,2-F migration is reversible under short-wavelength UV irradiation, thus leading back to the Lewis acid-base adduct.
低温基质实验表明，三苯基卡宾在两步反应中插入 BF 极强的 B-F 键。第一步是单重态二苯卡宾和 BF 之间形成强结合的路易斯酸碱络合物。这一步涉及卡宾的自旋态从三重态到单重态的反转。第二步需要可见光光化学激活，以诱导从硼到相邻碳原子的 1,2-F 迁移，在形成卡宾中心插入 BF 的形式插入产物的同时。在短波长 UV 照射下，1,2-F 迁移是可逆的，从而回到路易斯酸碱加合物。
