Photo-Lewis Acid Generator Based on Radical-Free 6π Photo-Cyclization Reaction
Photo-Lewis Acid Generator Based on Radical-Free 6π Photo-Cyclization Reaction
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基于无自由基6π光环化反应的光路易斯酸发生器
DOI：
10.1021/jacs.9b11821
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发表时间：
2019
影响因子：
15
通讯作者：
Kawai Tsuyoshi
中科院分区：
文献类型：
--
作者：
Mizutsu Ryo;Asato Ryosuke;Martin Colin J.;Yamada Mihoko;Nishikawa Yoshiko;Katao Shohei;Yamada Miku;Nakashima Takuya;Kawai Tsuyoshi
本文提出了一种基于光化学6π-过环化的光活性分子作为光-刘易斯酸发生器（PLAG）。在光照射下，PLAG分子产生了一个带有三氟酸反阴离子的缩合芳香碳正离子，表现出Lewis酸化学催化活性，如引发环氧单体聚合和催化Mukaiyama-aldol反应。用Lewis酸片段对环氧树脂聚合中的端-端结构进行了修饰。碳正离子诱导Mukaiyama-aldol反应是一种新的光门控体系，具有很高的催化活性和高于60的周转率。碳正离子生成的光化学量子产率为50%，大大高于大多数Brønsted光酸发生器。
We present here a new photo-active molecule which acts as a photo-Lewis acid generator (PLAG) based on photo-chemical 6π-percyclization. Photo-illumination of the PLAG molecule produces a condensed aromatic carbocation with a triflate counteranion, which exhibits Lewis acid chemical catalytic reactivity such as initiation of the polymerization of epoxy monomers and catalysis of Mukaiyama-aldol reactions. The terminal-end structure in the epoxy polymerization was modified with the Lewis acid fragment. The carbocation induced the Mukaiyama-aldol reaction as a new photo-gated system with remarkably high catalytic reactivity and turnover numbers higher than 60. The photo-chemical quantum yield of the carbocation generation is 50%, which is considerably higher than obtained with most Brønsted photo-acid generators.