Palladium-Catalyzed Amide-Directed Enantioselective Carboboration of Unactivated Alkenes Using a Chiral Monodentate Oxazoline Ligand
Palladium-Catalyzed Amide-Directed Enantioselective Carboboration of Unactivated Alkenes Using a Chiral Monodentate Oxazoline Ligand
复制标题
使用手性单齿恶唑啉配体进行钯催化的酰胺定向对映选择性碳硼化未活化的烯烃
DOI：
10.1021/acscatal.9b01350
复制
发表时间：
2019-07-01
期刊：
影响因子：
12.9
通讯作者：
He, Gang
中科院分区：
文献类型：
--
作者：
Bai, Zibo;Zheng, Sujuan;He, Gang
用第二代手性单齿恶唑啉(MOXca)配体催化未活化的烯烃与C-H亲核试剂和B(2)Pin(2)的1，2-碳硼对映选择性反应。MOXca配体具有N-连接咔唑侧臂的模块化设计，可以很容易地从丝氨酸和NH-咔唑合成，并提供了进一步改进的AQ导向的相对于MoXin配体的核对映体控制。在该双官能化反应体系中，KTFA添加剂和TFE溶剂的使用是获得高反应活性的关键。初步研究表明，在相同条件下，3-丁烯胺与亚胺N-亲核剂和B(2)Pin(2)进行的1，2-氨基取代反应产率高，对映体选择性高。
A Pd-catalyzed carboxamide-directed enantioselective 1,2-carboboration reaction of unactivated alkenes with C-H nucleophiles and B(2)Pin(2) has been developed using a second generation of chiral monodentate oxazoline (MOXca) ligand. The MOXca ligand featuring a modular design of a N-linked carbazole side arm can be readily synthesized from serine and NH-carbazoles and provided further improved enantiocontrol of the AQ-directed nucleopalladation over MOXin ligand. The use of KTFA additive and TFE solvent was critical to obtain high reactivity in this difunctionalization reaction system. Preliminary study showed that 1,2-aminoboration of 3-butenamide with imide N-nucleophiles and B(2)Pin(2) under the same conditions proceeded in good yield and high enantioselectivity.