225098-20-4

Upstream product

• 106-37-6 1.4-dibromobenzene 
• 225098-34-0 9-p-bromophenylfluoren-9-yl bromide 
• 875433-31-1 (2S)-N-[9-(4-bromophenyl)-9-fluorenyl]alanine tert-butyl ester 
• 225098-19-1 N-[9-(4-bromophenyl)-9-fluorenyl]alanine methyl ester 
• 486-25-9 9-fluorenone 

Downstream Products

• 875433-31-1 (2S)-N-[9-(4-bromophenyl)-9-fluorenyl]alanine tert-butyl ester 
• 875433-33-3 N-(9-(4-bromophenyl)-9-fluorenyl)alaninyl-ω-N-(tert-butoxycarbonyl)lysine tert-butyl ester 
• 225098-35-1 2-[9-(4-bromo-phenyl)-9H-fluoren-9-ylamino]-1-phenyl-propan-1-ol 
• 875433-34-4 N-(9-(4-morpholinophenyl)-9-fluorenyl)alaninyl-ω-N-(tert-butoxycarbonyl)lysine tert-butyl ester 
• 875433-32-2 (2S)-N-(9-(4-morpholinophenyl)-9-fluorenyl)alanine tert-butyl ester 
• 225098-22-6 (2S)-N-(9-p-bromophenylfluoren-9-yl)alanine isoxazolidine 

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.

A novel linking-protecting group strategy for solid-phase organic chemistry with configurationally stable α-[N-(phenylfluorenyl)]amino carbonyl compounds: Synthesis of enantiopure norephedrines on solid support

A novel linking strategy has been developed for synthesizing configurationally stable α-amino aldehyde on polymeric supports. Alkylation of L-alanine methyl ester with 9-bromo-9-p-bromophenylfluorenene, followed by ester hydrolysis and coupling to isoxazolidine, provided N-(9-p- bromophenylfluoren-9-yl)alanine isoxazolidide (5), which was transformed into its corresponding boronate 2 by a palladium-catalyzed cross-coupling reaction with diboron pinacol ester. Boronate 2 was anchored to four different polymeric aryl halides 6-9 in 70-99% yields. Polymer-bound alaninal 1b was then synthesized on non-cross-linked polystyrene by hydride reduction of isoxazolidide 10b. Treatment of alaninal 1b with phenylmagnesium bromide, cleavage of the resulting amino alcohol in a 1:2:2 TFA/CH2Cl2/anisole cocktail, and acylation with di-tert-butyl dicarbonate furnished N- (BOC)norephedrines 14 that were demonstrated to be enantiopure by conversion to diastereomeric thioureas 15 and analysis by HPLC. In summary, we have developed a process by which the 9-phenylfluoren-9-yl protecting group has been converted into a new linker for the solid-phase synthesis and manipulation of α-amino carbonyl compounds.