含噁唑啉环的苯并咪唑卡宾配体的设计合成及其在催化加成反应中的应用研究

以L-苯丙氨酸和苯并咪唑为原料,首次设计合成了一类具有新型结构的含噁唑啉环的苯并咪唑卡宾配体.首先将氨基酸还原和氨基酰化保护,然后将保护产物与苯并咪唑偶联,并构筑噁唑环,最后合成季铵盐等5步反应高效合成了6种具有中心手性的氮杂卡宾配体（NHC）6（A～F）.利用1 HNMR和13CNMR对相关产物进行了表征,同时利用二维核磁共振技术对重要的中间体5进行了结构表征,结果表明成功合成了目标配体,并确定化合物5为R-构型.研究了其对吲哚与C=O、C=N加成反应的催化性能,在C—C键的构筑中,将氮杂环卡宾配体6分别与Pd（Ⅱ）、Cu（Ⅱ）和Ag（Ⅰ）络合,得出最优反应条件为：6F为配体,二氯甲烷为溶剂、氧化银为碱、醋酸钯为金属,最高收率可达91%.在进一步的C—N键构筑的研究中,筛选出最优配体为6A,最高收率为89.4%.

The design and synthesis of novel benzimidazole carbene ligands and catalytic study on addition reactions

Benzimidazole carbene ligands（NHC） 6（A~F） with oxazoline ring was first synthesized efficiently through five steps：reduction,acylation,connection with benzimidazole,formation of oxazoline ring using（L）-phenylalanine and benzimidazole as the starting materials.By means of 1H NMR and 13C NMR spectra analysis,it was demonstrated that benzimidazole was connected with oxazoline successfully,and the chemical shifts were fully assigned via several kinds of 2D NMR experiments.As a result,the R-configuration and the connection among the atoms of 5 were determined.To determined the catalytic properties of ligands 6（A~F）,they are used to catalyze C=C,C=N addition reactions.In the catalytic reaction of C—C bond formation,complexes of 6 with Pd（Ⅱ）、Cu（Ⅱ） and Ag（Ⅰ） were used,and the optimal conditions were achieved,that is 6F as ligand,dichloromethane as solvent,AgO as base and Pd（OAc）2 was used.The optimal catalytic yield is 91%.For the C=N addition reactions,the best ligand is 6A,the yield is 89.4%.