The chemistry of Boron cation (boronium, borenium, borinium)-promoted transformation reaction

硼阳离子（硼、硼、硼）促进的转化反应的化学

• 批准号: 12440206
• 负责人: KIYOOKA Syun-ichi
• 金额: $ 7.3万
• 依托单位: Kyushu University (2002)Kochi University (2000-2001)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12440206/
• 关键词: boron cation; boronium ion; Lewi acidity; catalyst; ^<11>B NMR; ^<11>BNMR

This research was undertaken to study solvent effects on chiral oxazaborolidinone-promoted asymmetric aldol reaction, followed by detection of cationic boron species when the B-H bond of the oxazaborolidinone was changed to the B-X. Using the B-Br compound related to (R,R)-stien, existence of the boron species and its utilization to organic syntheses were investigated in detail. It turned out to be quite difficult to control two vacant orbitals of the hypothetical chiral boron cation in asymmetric reactions. In addition, the complete boron cations lead easily to neutral trivalent boronic compounds by attack of nucleophiles because of the extensively high electrophilicity and it is also difficult to catalytically recycle the boron cation. Thus, the reaction system should be necessarily restricted to some concerted reactions.Physical organic researches on boron cations were interestingly developed. Diphenylboron perchlorate, which was considered as a conventional standard compound of boron cations, was found to be a trivalent boronic compound having a covalent B-O bond by ^<11>B-NMR and calculation studies. Boron cation species in solution were suggested to be solvated tetravalent species, not divalent species. The true boron cationic species were detected for the first time by using laser flash-photolysis.

研究了溶剂对手性恶唑硼烷酮促进的不对称Aldol反应的影响，并通过将手性恶唑硼烷酮的B-H键转变为B-X键来检测阳离子硼物种.利用与（R，R）-苯乙烯有关的B-Br化合物，详细研究了硼物种的存在及其在有机合成中的应用。事实证明，在不对称反应中控制假设的手性硼阳离子的两个空轨道非常困难。此外，完全硼阳离子由于广泛的高亲电性而容易通过亲核试剂的攻击而导致中性三价硼化合物，并且也难以催化再循环硼阳离子。硼离子的物理有机研究取得了可喜的进展。通过~ 1H-B-NMR和计算研究发现，被认为是硼阳离子标准化合物的二苯硼高氯酸盐是一种具有共价B-O键的三价硼化合物<11>。溶液中的硼阳离子物种被认为是溶剂化的四价物种，而不是二价物种。首次利用激光闪光光解技术检测到了真正的硼阳离子物种。

项目成果

K.A.Shahid et al.: "A short synthesis of the C15-C21 segment of (+)-discodermolide, based on a ------"Tetrahedron Lett.. 43. 6373-6376 (2002)

K.A.Shahid 等人：“( )-discodermolide 的 C15-C21 片段的简短合成，基于 ------”Tetrahedron Lett.. 43. 6373-6376 (2002)

S.-i.Kiyooka: "Diphenylboron perchlorate as an efficient catalyst for self-and cross-condensation reactions of aldehydes having a-active hydrogens"Tetrahedron Lett.. 44. 927-930 (2003)

S.-i.Kiyooka：“二苯基硼高氯酸盐作为具有活性氢的醛的自缩合和交叉缩合反应的有效催化剂”Tetrahedron Lett.. 44. 927-930 (2003)

S.-i.Kiyooka, et al.: "A divergent syntheisis of essentially enantioixire syn-and anti-propionate aldol adducts based on the chiral 1,3,2-oxazaborolidin-5-one-promoted asymmetric aldol reaction followed by diastereoselective radical reduction"Bull. Chem.

S.-i.Kiyooka 等人：“基于手性 1,3,2-oxazaborolidin-5-one-促进的不对称羟醛反应，然后进行非对映选择性自由基，对本质上对映体顺式和反丙酸酯羟醛加合物进行发散合成

K. A. Shahid, Y. -N. Li, M. Okazaki, Y. Shuto, F. Goto, and S. -i. Kiyooka: "A short synthesis of the C15-C21 segment of (+)-discodermolide, based on an asymmetric approach from achiral 2-methyl-13-propanediol to versatile enantiopure stereotriads"Tetrahe

K.A.沙希德，Y.-N。

Kiyooka,S.i. et al.: "Efficient enantio-and diastereoselective synthesis of enantiopure syn-α-bromo-β-hydroxy-α-methyl propionate"Tetrahedron : Asymmetry. 11. 1537-1542 (2000)

Kiyooka, S.i. 等人：“对映体纯顺式-α-溴-β-羟基-α-甲基丙酸酯的高效对映体和非对映选择性合成”四面体：不对称性。