一系列二聚体配合物[TiL * X 2 ] 2(H 2 L * =(1 R,2 S)-2-(4-甲基苯磺酰基氨基)-1,3-二苯基-1-丙醇(5); X = O -我-Pr(4),NME 2(6),或O-吨-Bu(7))中制备,和所述不对称的Et 2的Zn添加到苯甲醛由复合物催化4,6,或7通过添加过量的Ti(O- i- Pr)4给出了高达96.3%ee的出色对映选择性。在11 H NMR研究表明,这些配合物的催化体系包括一种共同的活性中间体。的反应4用的Ti 2摩尔当量(O-我-Pr)4,得到另一二聚体复合,9,与该结构(我-Pro)2 TIL *的Ti(O-我-Pr)4。配合物9被证明可提供合适的环境,实现95.6%ee的对映选择性。复杂9在溶液中被示出为复合物的混合物4,9,和Ti(O-我-Pr)4,这三种配合物之间的平衡取决于溶剂和温度。配合物4或9与MeTi(O- i- Pr)3的反应提供了配合物(i
Structural and Electronic Effects in Asymmetric Diethylzinc Addition to Benzaldehyde Catalyzed by Titanium(IV) Complexes of <i>N</i>-Sulfonylated β-Amino Alcohols
作者:Kuo-Hui Wu、Han-Mou Gau
DOI:10.1021/om030515+
日期:2003.12.1
titanium(IV) complexes of (R,S)-3 were carried out, and yields and enantioselectivities of the desired (R)-1-phenylpropanol increase with increasing electron-donating abilities of R substituents. A dimeric titanium(IV) complex 4 was prepared, and the structure of 4 shows an interesting feature of inequivalent titanium metal centers with one sulfonamide of the chiral ligand bonded to a Ti metal center
由各种烷基或芳基的反应制得一系列N-磺酰化的β-氨基醇(R,S)-3,(1 R,2 S)-PhCH(OH)CH(NHSO 2 R)CH 2 Ph -磺酰氯与(1 R,2 S)-2-氨基-1,3-二苯基丙醇 阿1所的这些1 H NMR研究的配体示出了具有在磺酰基的R取代基的电子性质的配体的吸电子能力的相关性。(R,S)-3的钛(IV)配合物催化苯甲醛的不对称二乙基锌加成反应进行,所需的(R)-1-苯基丙醇的产率和对映选择性随R取代基的供电子能力的增加而增加。甲二聚钛络合物(IV)4制备,和结构4所示的不等价的钛金属中心与一个η键合的Ti金属中心的手性配体的一个磺酰胺基一个有趣的特点2 -时尚和另一磺酰胺键合到在η第二钛金属中心1 -时尚。络合物4不是用于不对称二乙基锌加成反应的有效催化剂。进一步添加Ti(O- i -Pr)4,所得体系变得有效,其结果几乎与原位形成的催化体系相同。另一个有趣的特征是1
Enantioselective addition of diethylzinc to aldehydes catalyzed by titanium(IV) complexes of N-sulfonylated amino alcohols with two stereogenic centers
作者:Jing-Song You、Ming-Yuan Shao、Han-Mou Gau
DOI:10.1016/s0957-4166(01)00522-5
日期:2001.11
Bidentate N-sulfonylated aminoalcohols with one or two stereogenic centers were prepared and applied as chiral ligands in the titanium(IV)-catalyzed asymmetric addition of diethylzinc to aldehydes, affording excellent enantioselectivities of up to 98% e.e.
Mechanism of Asymmetric Dialkylzinc Addition to Aldehydes Catalyzed by Titanium(IV) Complexes of <i>N</i>-Sulfonylated β-Amino Alcohols
作者:Kuo-Hui Wu、Han-Mou Gau
DOI:10.1021/om034298o
日期:2004.2.1
(i-PrO)2TiL*Ti(O-i-Pr)4. Complex 9 is demonstrated to provide a suitable environment, achieving an enantioselectivity of 95.6% ee. Complex 9 in solution is shown as a mixture of complexes 4, 9, and Ti(O-i-Pr)4, and the equilibrium among these three complexes is solvent and temperature dependent. The reaction of complex 4 or 9 with MeTi(O-i-Pr)3 furnished the complex (i-PrO)2TiL*Ti(O-i-Pr)3Me (10), which
一系列二聚体配合物[TiL * X 2 ] 2(H 2 L * =(1 R,2 S)-2-(4-甲基苯磺酰基氨基)-1,3-二苯基-1-丙醇(5); X = O -我-Pr(4),NME 2(6),或O-吨-Bu(7))中制备,和所述不对称的Et 2的Zn添加到苯甲醛由复合物催化4,6,或7通过添加过量的Ti(O- i- Pr)4给出了高达96.3%ee的出色对映选择性。在11 H NMR研究表明,这些配合物的催化体系包括一种共同的活性中间体。的反应4用的Ti 2摩尔当量(O-我-Pr)4,得到另一二聚体复合,9,与该结构(我-Pro)2 TIL *的Ti(O-我-Pr)4。配合物9被证明可提供合适的环境,实现95.6%ee的对映选择性。复杂9在溶液中被示出为复合物的混合物4,9,和Ti(O-我-Pr)4,这三种配合物之间的平衡取决于溶剂和温度。配合物4或9与MeTi(O- i- Pr)3的反应提供了配合物(i