| Project/Area Number |
11650888
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Synthetic chemistry
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| Research Institution | Kanazawa University |
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Principal Investigator |
SEGI Masahito Kanazawa University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (90135046)
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| Co-Investigator(Kenkyū-buntansha) |
HONDA Mitsunori Kanazawa University, Faculty of Engineering, Assistant Professor, 工学部, 助手 (60242533)
NAKAJIMA Tadashi Kanazawa University, Faculty of Engineering, Professor, 工学部, 教授 (70019735)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1999: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | Hydrozirconation / Phenylseleno Group / Vinylzirconocene / Dimethyltitanocene / Selenolester / Allylic Selenide / Selenoxide Elimination / [2,3]Sigmatropic Rearrangement / オレフィン化 / アルケニルセレニド / トランスメタル化 / 高次有機銅試薬 / ジルコナシクロペンテン |
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| Research Abstract |
Terminal alkynes (1) having a PhSe group on α or β carbonn atom contain three reactive sites (C-C triple bond, terminal alkynic hydrogen atom, PhSe group). Generally, hydrometalation of terminal alkynes takes place stereospecifically to give the E-alkenic metal species which are replaced by some electrophiles such as aldehydes, epoxides, and acyl halides to construct a new carbon-carbon bond. On the other hand, organoselenium chemistry became a very powerful tool in organic synthesis in recent times. Of particular importance is the owing to its easily handled nature.
1 reacted with zirconocene-ethylene complex to give regioselectively zirconacyclopentene derivatives. Hydrozirconation of 1 with Cp_2ZrHCl followed by transmetalation with Me_2Zn gave the corresponding terminal vinylzinc intermediates regio-and stereoselectively, which underwent the coupling reaction with aldehydes to afford the allylic alcohol derivatives having a phenylseleno group. Terminal hydrogen atom of 1 was easily abstracted by n-BuLi at-78℃ to generate sp carbanion species which were effectively trapped by aldehydes on epoxides. The compounds with a phenylseleno group were oxidized with excess amounts of H_2O_2 to yield the desired products having A-shaped olefinic alcohol moiety in good yields via selenoxide syn elimination.
Methylenation of phenylselenolesters with dimethyl titanocene (Cp_2TiMe_2) gave alkenyl selenides, which were subjected to oxidation with m-CPBA to afford terminal alkynes, not to allene, via selenoxide syn elimination. On the other hand, reaction of α-phenylseleno ketones with Cp_2TiMe_2 gave a mixture of isomeric allylic selenides and the subsequent oxidation by H_2O_2 led to the formation of allylic alcohols via [2,3] sigmatropic rearrangement.
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