Edel Klara, Yang Xinyu, Ishibashi Jacob S A, Lamm Ashley N, Maichle-Mössmer Cäcilia, Giustra Zachary X, Liu Shih-Yuan, Bettinger Holger F
Institut für Organische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.
Department of Chemistry, Boston College, Chestnut Hill, MA, 02467-3860, USA.
Angew Chem Int Ed Engl. 2018 May 4;57(19):5296-5300. doi: 10.1002/anie.201712683. Epub 2018 Mar 30.
The photochemistry of 1,2-dihydro-1,2-azaborinine derivatives was studied under matrix isolation conditions and in solution. Photoisomerization occurs exclusively to the Dewar valence isomers upon irradiation with UV light (>280 nm) with high quantum yield (46 %). Further photolysis with UV light (254 nm) results in the formation of cyclobutadiene and an iminoborane derivative. The thermal electrocyclic ring-opening reaction of the Dewar valence isomer back to the 1,2-dihydro-1-tert-butyldimethylsilyl-2-mesityl-1,2-azaborinine has an activation barrier of (27.0±1.2) kcal mol . In the presence of the Wilkinson catalyst, the ring opening occurs rapidly and exothermically (ΔH=(-48±1) kcal mol ) at room temperature.
在基质隔离条件下和溶液中研究了1,2-二氢-1,2-氮杂硼烷衍生物的光化学性质。用紫外光（>280 nm）照射时，光异构化仅发生为狄瓦耳价异构体，量子产率很高（46%）。用紫外光（254 nm）进一步光解会生成环丁二烯和一种亚氨基硼烷衍生物。狄瓦耳价异构体热开环反应回到1,2-二氢-1-叔丁基二甲基硅基-2-均三甲苯基-1,2-氮杂硼烷的活化能垒为(27.0±1.2) kcal mol 。在威尔金森催化剂存在下，开环在室温下迅速发生且放热（ΔH=(-48±1) kcal mol ）。
