ASYMMETRIC ALLYLATION REACTION OF IMINES WITH CHIRALLY MODIFIED ALLYLMETALS

虽然有机金属试剂亲核加成的光学活性胺的对映选择性合成是当前感兴趣的一个课题，但与羰基化合物的不对称加成相比，烯丙基金属对映选择性加成C=N双键的研究还很不发达。本课题旨在设计亚胺的不对称烯丙化反应，我们发现n -金属亚胺如n -硅基、n -铝基和n -硼基与烯丙基硼试剂发生烯丙化反应，得到相应的同质烯丙胺，收率较高。从同丙烯胺中去除n取代基是很容易的。因此，这种方法是合成光学活性伯同戊烯胺的一种新颖有效的方法。例如，用手性修饰的烯丙基硼试剂对n -硅胺进行对映选择性烯丙基化，得到了几乎定量产率且对映选择性高（> - 90% ee）的同型烯丙胺。据我们所知，这是首次报道烯基硼试剂在亚胺上的对映选择性加成实现了高水平的不对称诱导。虽然由烯化醛衍生的n -硅胺作为烯丙化的产物形成络合混合物，但具有α质子的n -铝亚胺可以烯丙化得到同型烯丙胺。在n -铝亚胺和n -硼基亚胺的对映选择性烯丙基化反应中，可以得到对映富集的同丙烯胺，产量高，选择性高。值得注意的是，即使在室温下，这些亚胺的烯化反应也具有很高的对映选择性（bbb80 % ee）。聚合物负载的手性试剂和催化剂因其可多次循环使用而成为不对称合成领域的研究热点。在某些情况下，通过使用聚合物负载的手性催化剂，可以实现连续流动系统。制备了聚合物负载的手性改性烯丙基硼试剂。研究了上述n -金属亚胺与聚合物载体试剂的不对称烯丙化反应。由d -樟脑或去甲麻黄碱衍生的聚合物负载的n -磺酰氨基醇是亚胺烯丙化反应的合适手性配体。尽管使用这种聚合物进行非均相反应，但获得了足够的反应活性和较高的对映选择性。这也是首次使用聚合试剂对亚胺进行对映选择性烯丙基化的发现。少

Although the enantioselective synthesis of optically active amines by nucleophilic addition of organometallic reagents is a topic of current interest, the enantioselective addition of allylmetals to C=N double bond is quite underdeveloped in comparison to the effort on record in the area of asymmetric addition to carbonyl compounds. This research project aimed at design of asymmeric allylat ion reaction of imines, We have found that N-metallo imines such as N-silyl, N-aluminum, and N-borylimines were allylated with allylboron reagents to give the corresponding homoallylamines in good yield. Removal of N-substituents from the homoallylamines were quite easy. This approach is thus a novel efficient method for the synthesis of optically active primary homoallylamines. For example, N-silylimines were enantioselectively allylated with chirally modified allylboron reagent to give the homoallylamines in almost quantitative yield with high enantioselectivity (> 90% ee). To our knowledge, this … More is the first report of high level of asymmetric induction realized in the enantioselective addition of allylboron reagent to imines. Although N-silylimines derived from enolizable aldehydes resulted in the formation of complexed mixture as the product of allylat ion, N-alumino imines having alpha-proton could be allylated to give the homoallylamine. In the cases of the enantioselective allylation of N-alumino imines and N-boryl imines afforded the enantioenriched homoallylamines in good yield with high selectviity. It is noteworthy that high enantioselectivty (>80% ee) was attained even at room temperature when these imines were allylated.Polymer-supported chiral reagents and catalysts are of interest in the field of asymmetric synthesis, since the chiral reagents can be recycled many times. In some cases, continuous flow system is possible by using polymer-suppored chiral catalyst. We have prepared polymer- supported chirally modified allylboron reagents. Asymmetric allylation of N-metallo imines described above with the polymer-supported reagents have been investigated. Polymer- supported N-sulfonylaminoalcohols derived from D-camphor or norephedrine were quite suitable chiral ligands for the allylation of imines. In spite of heterogeneous reaction using such polymers, sufficient reactivity and high enantioselelctivity was attained. This is also the first finding of the enantioselective allylation of imines using polymeric reagent. Less