通过4-[(2-吡啶基)乙亚胺基]-2-戊烯-2-醇(1)与[(Me3Si)2N]3Y(μ-Cl)Li(THF)3的反应,制备含吡啶基β-烯酮亚胺NNO型钇双胺基配合物(2),采用1 H NMR,13 C NMR,元素分析,X-ray和IR等对该配合物进行了表征,并探索了其在催化异戊二烯聚合中...通过4-[(2-吡啶基)乙亚胺基]-2-戊烯-2-醇(1)与[(Me3Si)2N]3Y(μ-Cl)Li(THF)3的反应,制备含吡啶基β-烯酮亚胺NNO型钇双胺基配合物(2),采用1 H NMR,13 C NMR,元素分析,X-ray和IR等对该配合物进行了表征,并探索了其在催化异戊二烯聚合中的应用.结果表明,配合物2在催化异戊二烯聚合方面有较好的催化活性和立体选择性.展开更多
The selectivities, including peri-, regio-, and diastereoselectivities, in the Staudinger reaction involving vicinal diimines and ketenes were investigated theoretically via the density functional theory （DFT） calcu...The selectivities, including peri-, regio-, and diastereoselectivities, in the Staudinger reaction involving vicinal diimines and ketenes were investigated theoretically via the density functional theory （DFT） calculation. The results indicate that vicinal diimines prefer stepwise [2＋2] cycloaddition rather than [2＋4] cycloaddition to generate cis-4-imino-β-lactams. The diimines attack the less sterically hindered exo-side of ketenes to generate zwitterionic intermediates, which directly undergo a conrota- tory ring closure to produce cis-4-imino-β-lactams whatever diimines with less or more bulky N-substituents. For unsymmetric vicinal ketoaldehyde-derived diimines, their ketimines attack the exo-side of ketenes and undergo a conrotatory ring closure to produce cis-4-aldimino-β-lactams due to less steric effect. The current theoretical studies provide very important information for in-depth understanding of the selective formation of mono-cis-β-lactams from vicinal diimines and ketenes.展开更多
文摘通过4-[(2-吡啶基)乙亚胺基]-2-戊烯-2-醇(1)与[(Me3Si)2N]3Y(μ-Cl)Li(THF)3的反应,制备含吡啶基β-烯酮亚胺NNO型钇双胺基配合物(2),采用1 H NMR,13 C NMR,元素分析,X-ray和IR等对该配合物进行了表征,并探索了其在催化异戊二烯聚合中的应用.结果表明,配合物2在催化异戊二烯聚合方面有较好的催化活性和立体选择性.
文摘The selectivities, including peri-, regio-, and diastereoselectivities, in the Staudinger reaction involving vicinal diimines and ketenes were investigated theoretically via the density functional theory （DFT） calculation. The results indicate that vicinal diimines prefer stepwise [2＋2] cycloaddition rather than [2＋4] cycloaddition to generate cis-4-imino-β-lactams. The diimines attack the less sterically hindered exo-side of ketenes to generate zwitterionic intermediates, which directly undergo a conrota- tory ring closure to produce cis-4-imino-β-lactams whatever diimines with less or more bulky N-substituents. For unsymmetric vicinal ketoaldehyde-derived diimines, their ketimines attack the exo-side of ketenes and undergo a conrotatory ring closure to produce cis-4-aldimino-β-lactams due to less steric effect. The current theoretical studies provide very important information for in-depth understanding of the selective formation of mono-cis-β-lactams from vicinal diimines and ketenes.
