Development of A Chiral Homoenolate Equivalent which Reacts Selectively with Imines
Development of A Chiral Homoenolate Equivalent which Reacts Selectively with Imines
批准号:
12650847
负责人:
OKAMOTO Sentaro
金额:
$2.37万
依托单位国家:
日本
项目类别:
Grant-in-Aid for Scientific Research (C)
财政年份:
2000
资助国家:
日本
项目状态:
已结题
起止时间:
2000 至 2001
中文摘要
由光学活性的丙烯醛1,2-二环己基乙烯缩醛与二价钛试剂Ti(O-i-Pr)_4/2 i-PrMgCl原位反应制备的手性烯丙基钛化合物,与各种无环和环状亚胺以区域特异性方式反应,以良好的合并产率得到E-和Z-异构体的混合物形式的α-加成产物,其中前者以92:8至>95:5的比例占主导地位。将(E)-和(Z)-加合物的混合物和在几种情况下可以分离的纯(E)-加合物分别转化为相应的β-氨基酯以确定绝对构型和对映体纯度。对于(E)-和(Z)-加成产物的混合物,新形成的不对称中心的ee大于78%,而对于纯的(E)-异构体,新形成的不对称中心的ee大于96%。利用乙烯基醚在反应产物中的多功能性,可以方便地制备光学活性的γ-氨基醛、γ-氨基醛缩醛、γ-氨基酸、β-氨基酯和吡咯烷基异喹啉。在烯丙基钛与光学活性α-甲硅烷基氧基亚胺的反应中,观察到显著的双立体分化;因此,衍生自(S,S)-或(R,R)-1,2-二环己基乙烯缩醛的烯丙基钛的反应分别以55:45或0:100的比例提供顺式加合物和反式加合物。与β-硅氧亚胺反应产物的立体化学主要受烯丙基钛的控制。该反应可有效地用于合成巴茨拉定D的关键中间体4-氨基-6-羟基十五醛二甲缩醛的合成。
英文摘要
A chiral allyltitanium compound, prepared in situ by the reaction of optically active acrolein 1,2-dicyclohexylethylene acetal with a divalent titanium reagent, Ti(O-i-Pr)_4/2i-PrMgCl, reacts with a variety of acyclic and cyclic imines in a regiospecific way to afford cc-addition products as a mixture of the E- and Z-isomers in good combined yield, where the former is predominant in a ratio of 92:8 to >95:5. The mixture of (E)- and (Z)-adducts and pure (E)-adducts which could be isolated in several cases were respectively converted to the corresponding β-amino esters to confirm the absolute configuration and enantiomeric purity. The ee of the newly-formed asymmetric center is more than 78 % for the mixture of (E)- and (Z)-addition products and more than 96 % for pure (E)-isomer. By taking advantage of the versatility of the vinyl ether moiety in reaction products, optically active γ-amino aldehydes, γ-amino aldehyde acetals, y-amino acids, β-amino esters, andpyrrolidinoisoquinolines were readily prepared. In the reaction of the allyltitanium with optically active cc-silyloxyimine, remarkable double stereodifferentiation was observed; thus, the reaction of the allyltitanium derived from (S,S)- or (R,R)-1,2-dicyclohexylethylene acetal provided syn- and anti-adducts in a ratio of 55 : 45 or 0 : 100 respectively. Meanwhile, the stereochemistry of the product in the reaction with β-silyloxyimine was controlled mainly by the allyltitanium. The reaction could be effectively applied to prepare 4-amino-6-hydroxypentadecanal dimethyl acetal, a key intermediate for the synthesis of batzelladine D.
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Sentaro Okamoto: "Titanium (IV) Aryloxide Catalyzed Cyclization Reactions of 1,6-and 1,7-Dienes"J.Am.Chem.Soc.. 122. 1223-1224 (2000)
Sentaro Okamoto:“钛 (IV) 芳基氧化物催化 1,6-和 1,7-二烯的环化反应”J.Am.Chem.Soc.. 122. 1223-1224 (2000)
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Sentaro Okamoto, Fumie Sato: "A Highly Efficient and Practical Preparation of 2,4-Pentadienyltitaniums and their γ-Selective Addition Reaction with Aldehydes and Ketones"J. Organomet. Chem.. 624. 151-156 (2001)
Sentaro Okamoto、Fumie Sato:“2,4-戊二烯基钛的高效实用制备及其与醛和酮的 γ-选择性加成反应”J. Organomet. 624. 151-156 (2001)
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Sentaro Okamoto: "An Efficient and Practical Preparation of Optically Active syn-1-Vinyl-2-amino Alcohol Derivatives by the Regio-and Diastereoselective Addition Reaction of (γ-Alkoxyallyl) titaniums with Chiral Imines.Formal Synthesis of Statine"Tetrahed
Sentaro Okamoto:“通过(γ-烷氧基烯丙基)钛与手性亚胺的区域和非对映选择性加成反应,高效实用地制备光学活性 syn-1-Vinyl-2-amino 醇衍生物。他汀的正式合成”
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Sentaro Okamoto: "General synthetic method for preparation of optically active propargyl and allenylstannanes"Tetrahedron Letters. 42. 6323-6326 (2001)
Sentaro Okamoto:“制备光学活性炔丙基和联烯基锡烷的通用合成方法”Tetrahedron Letters。
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Sentaro Okamoto, Xin Teng, Shintaro Fujii, Yuuki Takayama, Fumie Sato: "An Allyltitanium Derived from Acrolein 1,2-Dicyclohexylethylene Acetal and (η%^2-propene)Ti(O-i-Pr)_2 as a Chiral Propionaldehyde Homoenolate Equivalent Which Reacts with Imines with
Sentaro Okamoto、Xin Teng、Shintaro Fujii、Yuuki Takayama、Fumie Sato:“由丙烯醛 1,2-二环己基乙烯缩醛和 (η%^2-丙烯)Ti(O-i-Pr)_2 衍生的烯丙基钛,作为手性丙醛高烯醇化物等价物,其中与亚胺反应
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共 22 条
Development of Cleavage Reactions of C-O and N-S Bonds Promoted by Novel Low-Valent Titanium Reagents and Their Synthetic Applications
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批准号:22550103
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项目类别:Grant-in-Aid for Scientific Research (C)
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资助金额:$3.08万
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财政年份:2010
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负责人:OKAMOTO Sentaro
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依托单位:
New Low Valent Titanium Reagents and Their Application to Bond-Forming and-Cleaving Reactions
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批准号:19550113
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项目类别:Grant-in-Aid for Scientific Research (C)
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资助金额:$3.08万
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财政年份:2007
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负责人:OKAMOTO Sentaro
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依托单位:
Stereoselective Synthesis of a-Branched Amines Based on Formation of Azatitanacyclic Compounds
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批准号:16550102
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项目类别:Grant-in-Aid for Scientific Research (C)
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资助金额:$2.37万
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财政年份:2004
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负责人:OKAMOTO Sentaro
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依托单位:
Tandem Inter-/intramolecular Coupling Mediated by a Ti(II) Reagent : One-step Multibond-forming Reactions
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批准号:14550819
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项目类别:Grant-in-Aid for Scientific Research (C)
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资助金额:$2.24万
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财政年份:2002
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负责人:OKAMOTO Sentaro
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依托单位:
A Highly Efficient Synthesis of Cyclic Carbonyl Compounds via Acetylene-or Olefin-Titanium Complex
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批准号:07651047
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项目类别:Grant-in-Aid for Scientific Research (C)
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资助金额:$1.09万
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财政年份:1995
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负责人:OKAMOTO Sentaro
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依托单位:
海外基金