2021 Fiscal Year Final Research Report

Catalytic Asymmetric Dehydro-Diels-Alder Reaction for the Construction of Fused Polycyclic Heteroaromatics

Research Project

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Project/Area Number	19K05485
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 33020:Synthetic organic chemistry-related
Research Institution	Waseda University
Principal Investigator	Shibata Takanori 早稲田大学, 理工学術院, 教授 (80265735)
Project Period (FY)	2019-04-01 – 2022-03-31
Keywords	脱水素型Diels-Alder反応 / 縮合多環式化合物 / ヘテロ原子 / 炭素－硫黄結合開裂 / 光触媒
Outline of Final Research Achievements	There are several patterns of dehydro-Diels-Alder (DDA) reaction. For example, the tetradehydro-Diels-Alder (TDDA) reaction of a 1,3-enyne and alkyne gives a substituted benzene ring with perfect atom-economy. We merged two types of DDA reactions and realized the facile preparation of dibenzosilole-fused polycyclic compounds. Moreover, the benzene ring in the obtained silicon-containing cycloadduct showed high reactivity as a 1,3-diene moiety. On the other hand, we developed a Ni-catalyzed transformation initiated by non-activated C-S bond cleavage at ambient temperature along with carbothiolation to alkynes. An intramolecular reaction of diarylthioether-tethered 1,8-diyne gave sulfur-containing tetracyclic compounds. It is notable that an intermolecular reaction can also be achieved: self- and cross-coupling proceeded in complete regioselective manner. We further demonstrated the photo-catalytic activity of the obtained tetracyclic compounds in the benzylic oxidation.
Free Research Field	合成有機化学
Academic Significance and Societal Importance of the Research Achievements	環境負荷の小さい合成変換反応の開発は、有機化学者に課せられた使命と言える。今回報告者は、原子効率が100%である新規な形式の連続反応により、縮合多環式化合物の効率合成を達成した。ケイ素架橋テトラインの反応で、2種の連続的脱水素Diels-Alder反応により含ケイ素七環式化合物を合成し、さらのこの環化体が高い1,3-ジエン活性を有することを見いだした。一方、硫黄架橋の1,8-ジインの反応では、Ni触媒を用いることにより室温でC-S結合の開裂、さらに連続的なアルキン挿入により含硫黄四環式化合物を合成し、さらのこの環化体がトルエン類の選択的空気酸化において、光触媒として機能することを見いだした。