Development of Synthetic Methods Based on Generation of Low-Valent Titaniums

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K05869
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Synthetic chemistry
• Research Institution: Kanagawa University
• Principal Investigator: Okamoto Sentaro 神奈川大学, 工学部, 教授 (00201989)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 低原子価チタン / 精密有機合成 / 環化反応 / 環化付加反応 / McMurryカップリング

Outline of Final Research Achievements

The purposes are development of novel methods for generating new low-valent titanium species and their use for developing new synthetic reactions and catalyses. Synthesis of novel vitamin D derivatives by using highly stereoselective cyclization of enyne substrates mediated by the divalent-titanium and their binding ability to the human vitamin D receptor protein were accomplished. In addition, the titanacyclopentene intermediates derived from enyne substrates and the divalent-titanium could react with bis-electronic reagent such as ethyl formate to undergo bicyclizaiton reaction affording bicyclic cyclopentenol derivatives. A new dual-mode polymerization method was also developed, in which a Ti(O-i-Pr)4/Me3SiCl/Mg reagent simultaneously promoted McMurry coupling of dialdehydes and cyclotrimerization of aldehyde-alkynes in one-flask and the reaction gave branched polymers. CpTiCl3/Mg/Me3SiCl reagents were developed as new low-valent titanium catalyst for alkyne [2+2+2] cycloaddition.

Free Research Field

有機化学，有機合成化学，合成有機金属化学

Academic Significance and Societal Importance of the Research Achievements

低原子価チタン反応剤について，二価チタン等価反応剤の高度利用の事例を示したことでこの反応剤のより広範囲での利用を促進し，有機合成化学分野に寄与できるものと考えられる。また，新たな低原子価チタンの発生法を開発し，新規なdual-modeカップリング重合法およびアルキン[2+2+2]環化付加反応の新触媒系を開発したことは，高分子合成化学および有機合成・触媒化学の分野に起用できる成果で有ると考えられる。