School of Pharmaceutical Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University , Kakuma-machi, Kanazawa 920-1192, Japan.
Department of Chemistry, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States.
J Org Chem. 2017 Dec 15;82(24):13034-13042. doi: 10.1021/acs.joc.7b01981. Epub 2017 Nov 21.
Thermal reactions of benzo[3,4]cyclodec-3-ene-1,5-diyne with N-heterocyclic carbene boranes (NHC-boranes) provided mixtures of 9-borylated 1,2,3,4-tetrahydroanthracenes along with 1,2,3,4-tetrahydroanthracene. These products indicate that NHC-boranes serve as hydrogen donors to a p-benzyne intermediate formed by the Masamune-Bergman reaction. Experimental results support a radical mechanism in nonpolar solvents, but suggest that ionic mechanisms compete in the production of 1,2,3,4-tetrahydroanthracene when the reaction is performed in a polar solvent.
苯并[3,4]环癸-3-烯-1,5-二炔与 N-杂环卡宾硼烷（NHC-硼烷）的热反应提供了 9-硼化 1,2,3,4-四氢蒽与 1,2,3,4-四氢蒽的混合物。这些产物表明，NHC-硼烷作为由 Masamune-Bergman 反应形成的 p-苯炔中间体的氢供体。实验结果支持非极性溶剂中的自由基机理，但当反应在极性溶剂中进行时，表明离子机理在 1,2,3,4-四氢蒽的生成中竞争。
