Preparation of Dicarbonyl[hydrotris(1-pyrazolyl)borato](η<sup>3</sup>-allyl)molybdenum Complexes Bearing Electron-Donating Substituents (1-((<i>tert</i>-Butyldimethylsilyl)oxy), 1-Alkoxy, and 1-Acetoxy) via the Nucleophilic Addition of Mo(CO)<sub>3</sub>(DMF)<sub>3</sub> to Enals and Enones
作者:Yancey D. Ward、Lawrence A. Villanueva、Gary D. Allred、Lanny S. Liebeskind
DOI:10.1021/om9601256
日期:1996.10.1
disubstituted allyls bearing a 1-acetoxy substituent existed as mixtures of both possible syn/anti isomers and the syn/syn and anti/anti isomers. The conformation and configuration of the isomers was confirmed through nOe studies on several complexes and by X-ray crystallography in the case of [TpMo(CO)2[η-(1,2,3)-(±)-(1R,2S,3S)-1-methoxy-2-cyclohexen-1-yl].
Viability of a [2 + 2 + 1] Hetero-Pauson–Khand Cycloaddition Strategy toward <i>Securinega</i> Alkaloids: Synthesis of the BCD-Ring Core of Securinine and Related Alkaloids
Preliminary results related to the development of [2 + 2 + 1]-oxa-hetero-Pauson–Khand cycloaddition strategy toward the Securinegaalkaloids are reported. The critical tricyclic BCD-ring core was assembled in only nine linear steps from cheap 4-hydroxy-l-proline. The study provides valuable insight into the scope of a rare hetero-Pauson–Khand reaction, a powerful tool for the rapid construction of
Synthesis and Characterization of Stable Cationic [Hydrotris(1-pyrazolyl)borato]Mo(CO)(NO)(η<sup>3</sup>-allyl) ComplexesSolid-State and Solution Evidence for an η<sup>2</sup>-Allyl Structure
作者:Lawrence A. Villanueva、Yancey D. Ward、Rene Lachicotte、Lanny S. Liebeskind
DOI:10.1021/om960041x
日期:1996.10.1
were unstable in solution; however, using the noncoordinating counterion [(3,5-(CF3)2C6H3)4B]- (BAr‘4-) robust complexes were produced, permitting a thorough spectroscopic investigation. The crystal structure of [TpMo(CO)(NO)(η3-C3H5)][(3,5-(CF3)2C6H3)4B] revealed a significant η3 → η2 distortion of the allyl moiety. HETCOR and COSY NMR experiments were conducted in order to assign the chemical shifts
从相应的TpMo(CO)2(π-烯丙基)配合物,制备了四个对称取代的TpMo(CO)(NO)(π-烯丙基)+配合物(π-烯丙基=丙烯基,2-甲基丙烯基,环己烯基和环辛烯基)并通过1 H和13 C NMR光谱对IR进行表征,在一种情况下通过X射线晶体学对其进行表征。的BF 4 -的亚硝酰基阳离子络合物的盐在溶液中是不稳定的; 然而,使用非配位抗衡离子[(3,5-(CF 3)2 C ^ 6 ħ 3)4 B] -(BAR” 4 -)产生了坚固的络合物,可以进行彻底的光谱研究。[TpMo(CO)(NO)(η的晶体结构3 -C 3 H ^ 5)] [(3,5-(CF 3)2 C ^ 6 ħ 3)4 B]揭示了显著η 3 →η 2失真烯丙基部分的基团。进行HETCOR和COZY NMR实验是为了明确分配每个烯丙基氢和碳原子的化学位移。这些数据还揭示了η 3 →η 2的烯丙基配合物的失真。1个为了确定每
Ward, Yancey D.; Villanueva, Lawrence A.; Allred, Gary D., Organometallics, 1995, vol. 14, # 9, p. 4132 - 4156
作者:Ward, Yancey D.、Villanueva, Lawrence A.、Allred, Gary D.、Payne, Sonha C.、Semones, Mark A.、Liebeskind, Lanny S.
DOI:——
日期:——
Stereocontrolled Oxidative Addition of Zerovalent Molybdenum to Enantiomerically Pure Allylic Acetates with Either Inversion or Retention at the Stereogenic Center
作者:Yancey D. Ward、Lawrence A. Villanueva、Gary D. Allred、Lanny S. Liebeskind