N,N '-Dioxide-scandium(III) complex catalyzed highly enantioselective Friedel-Crafts alkylation of indole to alkylidene malonates

作者：Liu Yanling; Zhou Xin; Shang Deju; Liu Xiaohua; Feng Xiaoming^*

来源：Tetrahedron, 2010, 66(7): 1447-1457.

DOI：10.1016/j.tet.2009.12.032

• Friedel-crafts alkylation
• Alkylidene malonates
• Indole derivatives
• N,N '-Dioxide-scandium(III)

A highly efficient enantioselective Friedel-Crafts alkylation of indoles with alkylidene malonates has been developed using chiral N,N'-dioxide LA-scandium(III) complex as the catalyst, giving the corresponding products in high yields with excellent enantioselectivities (up to 99% yield and 95% ee). The product 3a was facilely converted into several interesting compounds, such as tryptamines, indolepropionic acids and beta-carbolines. It is noteworthy that the seven-membered beta-carboline-like compound has been synthesized for the first time. Based on the crystal structure of the chiral N,N'-dioxide L10-scandium(III) complex, the proposed transition state and possible catalytic cycle were presented to elucidate the reaction mechanism.

• 出版日期2010-2-13
• 单位四川大学