Indolines to Indoles by Functionalized Elimination

Whereas the wealth of indoline-to-indole transformations involves dehydrogenation (Chapter 66), the fnnctionaliza-tion of an indoline and snbseqnent elimination to afford an indole is a method that has become increasingly popular. 

7-indolineglyoxylate (99%) [10]. Dalla Croce and colleagues used a sulfur ylide approach to indolines and indoles (equations 2 and 3) [11, 12]. Bromination (NBS, EtjN) of indoline 1 (R=R =Ph, R =H) gave 2-benzoyl-3-phenyl-1 -phenylsuKonylindole (90%). 

Indole Ring Synthesis From Natural Products to Drug Discovery, First Edition. Gordon W. Gribble. 2016 John Wiley Sons, Ltd. Published 2016 by John Wiley Sons, Ltd. 

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