Kashida Junki, Shoji Yoshiaki, Fukushima Takanori
Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan.
Chem Asian J. 2019 May 15;14(10):1879-1885. doi: 10.1002/asia.201900047. Epub 2019 Feb 19.
Efficient 1,2-carboboration reactions to the C=N bond of carbodiimides with 9-borafluorenes, which give rise to cyclic borane-amidine conjugates with a seven-membered BNC ring, are reported. The resulting cyclic borane-amidine conjugates can be hydrolyzed into an acyclic bifunctional biaryl compound carrying both boronic acid and amidine groups, rendering the utility of the two-step protocol for the synthesis of multi-functionalized molecular systems with a potential as a supramolecular building block. Furthermore, the conjugated structure of the cyclic boron-amidine compounds can be changed upon alkylation of the boron atom that increases the coordination number of boron. The combination of Lewis acid (borane) and conjugated base (amidine) provides rich structural diversity of heteroatom-containing π-conjugated systems.
报道了9-硼芴与碳二亚胺的C=N键进行的高效1,2-碳硼化反应，该反应生成具有七元BNC环的环状硼烷-脒共轭物。所得的环状硼烷-脒共轭物可水解为同时带有硼酸和脒基团的无环双功能联芳基化合物，这使得该两步法在合成具有作为超分子构建块潜力的多功能分子体系中具有实用性。此外，环状硼-脒化合物的共轭结构可在硼原子烷基化时发生变化，烷基化会增加硼的配位数。路易斯酸（硼烷）和共轭碱（脒）的组合提供了含杂原子的π-共轭体系丰富的结构多样性。
