The Dewar Isomer of 1,2‐Dihydro‐1,2‐azaborinines: Isolation, Fragmentation, and Energy Storage
作者:Klara Edel、Xinyu Yang、Jacob S. A. Ishibashi、Ashley N. Lamm、Cäcilia Maichle‐Mössmer、Zachary X. Giustra、Shih‐Yuan Liu、Holger F. Bettinger
DOI:10.1002/anie.201712683
日期:2018.5.4
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
在基质分离条件下和溶液中研究了 1,2-二氢-1,2-氮杂硼啉衍生物的光化学。在紫外光 (>280 nm) 照射下,光异构化仅发生在杜瓦价异构体上,具有高量子产率 (46%)。用紫外线(254 nm)进一步光解导致形成环丁二烯和亚氨基硼烷衍生物。杜瓦价异构体的热电环开环反应返回1,2-二氢-1-叔丁基二甲基甲硅烷基-2-均三甲苯基-1,2-氮硼烷,其活化势垒为(27.0±1.2) kcal mol -1 。在威尔金森催化剂存在下,开环在室温下快速且放热地发生(Δ H =(-48±1) kcal mol -1 )。