Indoline copper catalyzed synthesis

Scheme 33 Copper-catalyzed synthesis of indolines and related heterocycles...

DSM also have been interested in this type of transformation and, in 2005, filed a patent on the application of this copper-catalyzed process in the synthesis of enantiomerically enriched indoline-2-carboxylic acids [76]. In this protocol, (5)-2-bromophenylalanine was cydizedto the corresponding indoline-2-carboxylic acid using 0.01 - 2 mol% CuCl. 

Jin, H., Zhou, B., Wu, Z., Shen, Y., and Wang, Y. (2011). One-pot synthesis of substituted indolines via a copper-catalyzed sequential multicomponent/C-N coupling reaction. Tetrahedron Lett., 67, 1178-1182. 

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