875433-34-4

Upstream product

• 225098-20-4 (2S)-N-[9-(4-bromophenyl)-9-fluorenyl]alanine 
• 225098-19-1 N-[9-(4-bromophenyl)-9-fluorenyl]alanine methyl ester 
• 875433-31-1 (2S)-N-[9-(4-bromophenyl)-9-fluorenyl]alanine tert-butyl ester 
• 110-91-8 morpholine 
• 875433-33-3 N-(9-(4-bromophenyl)-9-fluorenyl)alaninyl-ω-N-(tert-butoxycarbonyl)lysine tert-butyl ester 

Relevant academic research and scientific papers

9-(4-Bromophenyl)-9-fluorenyl as a safety-catch nitro gen protecting group

The 9-(4-bromophenyl)-9-fluorenyl (BrPhF) group has been developed as a novel safety-catch amine protection. This relatively acid-stable protecting group can be successfully activated by palladium-catalyzed cross-coupling reaction of the aryl bromide with morpholine and then cleaved effectively under mild conditions using dichloroacetic acid and triethylsilane. Complementary conditions are reported for selective removal of the BrPhF group in the presence of tert-butyl esters and carbamates as well as deprotection of tert-butyl esters and carbamates in the presence of BrPhF amines.