本研究提供了光谱和实验证据,证明简并复分解对这类新兴手性催化剂的有效性至关重要。公开了两种非对映体复合物的分离和 X 射线表征,以及对此类引发剂新亲烯在促进闭环复分解过程中表现出的反应性和对映选择性模式的检查。只有当产生足够量的乙烯并且通过简并过程在 Mo 处以足够快的速度发生反转时,才能实现高对映选择性,而与引发亚烷基的立体化学特性无关(Curtin-Hammett 动力学)。对于经历快速互变的非对映金属配合物,金属中心的立体突变变得无关紧要,
groups has been achieved successfully with the reaction of allylbromide by using sodium perborate as a new catalyst in aqueous media. The advantage of this method is operationally simple, short reaction time, good yield, and simple workup conditions over the previously reported conventional methods such as amination, oxyalkylation reactions of allylbromide, and Friedel–Crafts allylation chemistry.
The invention relates to polyurethane-polyurea dispersions, also called PU dispersion, which contain aralkylamine-blocked isocyanate groups, and to their preparation and use. This blocking agent ahs a significantly lower deblocking temperature as compared with the prior art. Coatings produced from this dispersion have high hydrolysis resistances. The arylamine-blocked isocyanate groups are composed of polyisocyanates, polymeric polyols having average molar weights of 400 to 6000, at least one blocking agent, and either or both of nonionically hydrophilicizing compounds or compounds having at least one ionic or potentially ionic group.