二乙胺合三(5-甲基-2-苯并噻唑基)硼烷的晶体结构

标题化合物二乙胺合三（５－甲基－２－苯并噻唑基）硼烷（Ｃ２８Ｈ２９ＢＮ４Ｓ３（Ｍｒ＝５２７．５７）的晶体属于三斜晶系，空间群为Ｐ１，晶胞参数ａ＝０．３９７（８）ｎｍ，ｂ＝１．１７４２（６）ｎｍ，ｃ＝１．３１００（２）ｎｍ，α＝１０４．２９（２）°，β＝９２．９９（３）°，γ＝９８．５８（５）°，Ｖ＝１．３７９０ｎｍ３，Ｚ＝２，Ｄｃ＝１．２７０ｇ／ｃｍ３，μ（ＭｏＫα）＝２．８０４ｃｍ－１．结构的偏离因子Ｒ＝０．０６４８，Ｒｗ＝０．０７３７．结构测定表明，甲基取代基的电子效应导致硼碳键键长的平均化，预示杂环对硼原子的π－电子反馈与胺基氮原子对硼原子的反馈有彼消此长的关系．     

2,8,9-三氧杂-5-氮杂-1-硼杂双环[3,3,3]十一碳烷的合成

本文报导了具有N→B配位键的2,8,9-三氧杂-5-氮杂-1-硼杂双环[3,3,3]十一碳烷的合成及性质。化合物(1)的制备已有报导,而化合物(2),(3)则为新的化合物。我们研究了它们的成环条件,制备的最佳条件及化学稳定性。     

Direct preparation and structure determination of tertiary and secondary amine boranes from primary or secondary amine boranes

New secondary and tertiary amine borane derivatives were prepared in a one-pot reaction starting from primary amine boranes. The reaction involves treatment of an amine borane with 2 equivalents of s-BuLi at −78 °C. In general, mixtures of mono and di metallated products were obtained. Alkyl iodides and benzyl chloride reacted with the lithiated amine, but aldehydes and ketones were reduced. Conversion was high as determined by NMR, but moderate to low yields were obtained after chromatography, possibly due to decomposition on silica. Crystal structures were obtained for the compounds 3a, 3b and 3c.     

A highly efficient general synthesis of phosphine-borane complexes

A general synthesis of phosphine-borane complexes proceeding in high yield in a safe, green process from borane generated in situ from sodium borohydride is described. The procedure also allows simultaneous carbonyl reduction and phosphine-borane formation on air-sensitive bulky phosphine derivatives.     

Effect of conformational control of chiral oxazaborolidine by π-π stacking interaction of a pentafluorophenyl group toward asymmetric borane reduction

A pentafluorophenyl group can act as a stereo-controlling group in oxazaborolidine-catalyzed asymmetric borane reduction through intramolecular π-π stacking interaction with a phenyl group. The intramolecular π-π interaction in oxazaborolidine bearing pentafluorophenyl group is confirmed by calculations and ¹H NMR study. The interaction affects the enantioselectivity of the asymmetric reduction of acetophenone while the extent is small.     

Pentafluorphenyliod(III)-Verbindungen. 2. Fluor-Aryl Substitution an Iodtrifluorid: Synthese von Pentafluorphenylioddifluorid C6F5IF2 und Bis(pentafluorphenyl)iodonium Pentafluorphenylfluoroboraten [(C6F5)2I]+[(C6F5)nBF4−n]−

Pentafluorophenyliodine(III) Compounds. 2. Fluorine-Aryl Substitution Reactions on Iodinetrifluoride: Synthesis of Pentafluorophenyliodinedifluoride C₆F₅IF₂ and Bis(pentafluorophenyl)iodonium Pentafluorophenylfluoroborates[(C₆F₅)₂I]⁺[(C₆F₅)_nBF_4?n]^? Mono- and disubstitution can be achieved in the fluorine-aryl substitution reaction on the low-temperature phase IF₃ in CH₂Cl₂ at ?78°C depending on the aryl transfer reagent. With B(C₆F₅)₃ [(C₆F₅)₂I]⁺ [(C₆F₅)_nBF_4?n]^? (68% yield) and with Cd(C₆F₅)₂ C₆F₅IF₂ (97% yield) is obtained whereas with C₆F₅SiMe₃ no fluorine-aryl substitution takes place on IF₃ even under basic conditions (EtCN or F^? addition). At ?78°C in EtCN solution IF₃ does not disproportionate but attacks the solvent under formation of HF.     

Asymmetric reduction of representative ketones with a bis-chiral oxazaborolidine system

In recent years, many optically active β-amino alcohols, mostly derived from naturally occurring α-amino acids, have been incorporated into the asymmetric synthesis as chiral auxiliaries or ligands.1 An effective asymmetric catalysts, the oxazaborolidine-borane reagents, which were originally pioneered by Itsuno and Corey,2 were generally prepared from chiral β-amino alcohols by the reaction with boric acid or formed in situ in the presence of borane. These reagents provide excellent enanti…     

Functionalization of the macropolyhedral borate anion cluster [B22H22]: isolation and characterization of the OH and OEt derivatives

Preparation and characterization of the first derivatives of the fused macropolyhedral anion [B₂₂H₂₂]²⁻ are reported. The species [B₂₂H₂₁OH]²⁻ (1) and [B₂₂H₂₁OEt]²⁻ (2) are obtained from workup of the products of the reaction between HgBr₂ and [NBzlEt₃]₂[B₂₂H₂₂]; a cluster involving the conjoining of a closo-B₁₂ icosahedron with a nido-B₁₀ cluster. Washing the products with ethanol followed by thin-layer chromatography allows the isolation of 1 and 2, reproducibly, in yields of 27 and 20%, respectively. The species were characterized by NMR spectroscopy, elemental analysis and X-ray diffraction studies. The crystal structure determinations of the two species identify novel features. Apparently the influence of the O atoms in the ions [B₂₂H₂₁OH]²⁻ and [B₂₂H₂₁OEt]²⁻ results in the lengthening of what was a gunwale B---B connection adjacent to the junction of the two cages such that the distances are 2.180 and 2.230 Å, respectively. These latter are longer than the corresponding distance in the parent species [B₂₂H₂₂]²⁻, which is 2.09 Å; quite long for a normal B---B distance. Thus it is assumed that these B atoms, in 1 and 2, one of which bears the substituent, are not bonded to each other.     

Synthesis of phenanthroimidazole-based four coordinate organoboron compounds

The synthesis of N,C-coordinated organoboron compounds (B1-B4) based on phenanthroimidazole described. All the compounds were characterized by various spectroscopic techniques. Single crystal X-ray diffraction analysis of the compounds B1 and B3 revealed that the vicinity around the boron atom adopts tetrahedral geometry. Except compound B4, other organoboron compounds (B1-B3) does not show solvatochromism. All our newly synthesized organoboron compounds exhibited moderate to good solution state quantum yields (0.07–0.88) and moderate solid state quantum yields.