Tanaka Daiki, Konishi Akihito, Yasuda Makoto
Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Center for Atomic and Molecular Technologies, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Chem Asian J. 2021 Oct 18;16(20):3118-3123. doi: 10.1002/asia.202100873. Epub 2021 Sep 6.
The synthesis and isolation of atrane-type molecules 1E (E=Si, Ge, or Sn) having a cationic group 14 elemental center are reported. The cations 1E act as hard and soft Lewis superacids, which readily interact with various hard and soft Lewis basic substrates. The rigid atrane framework stabilizes the localized positive charge on the elemental center and assists the formation of the well-defined highly coordinated states of 1E . The cations were applied to the hydrodefluorination, Friedel-Crafts reaction, alkyne cyclization, and carbonyl reduction as Lewis acid catalysts. Most notably, [1Si][ClO ] exhibits unique chemoselectivity that depends on a solvent in the competitive reaction of silyl enol ether with a mixture of benzaldehyde dimethyl acetal and benzaldehyde. Our findings indicate the potential of hard and soft Lewis superacids in organic synthesis.
报道了具有阳离子型第14族元素中心的氮杂环丙烷型分子1E（E = Si、Ge或Sn）的合成与分离。阳离子1E作为硬软Lewis超酸，能与各种硬软Lewis碱性底物轻松相互作用。刚性的氮杂环丙烷骨架稳定了元素中心上的局部正电荷，并有助于形成1E定义明确的高配位态。这些阳离子作为Lewis酸催化剂应用于加氢脱氟、傅克反应、炔烃环化和羰基还原反应。最值得注意的是，[1Si][ClO]在硅烯醇醚与苯甲醛二甲基缩醛和苯甲醛混合物的竞争反应中表现出取决于溶剂的独特化学选择性。我们的研究结果表明硬软Lewis超酸在有机合成中的潜力。
