Related Experiment Video
Updated: Jun 8, 2026

Preparation of Enantiopure Non-Activated Aziridines and Synthesis of Biemamide B, D, and epiallo-Isomuscarine
Published on: June 13, 2022
The 9-phenyl-9-fluorenyl group for nitrogen protection in enantiospecific synthesis
Essi J Karppanen1, Ari M P Koskinen
1Department of Chemistry, Aalto University, School of Science and Technology, Aalto, Finland.
Abstract:
One of the biggest challenges in asymmetric synthesis is to prevent racemization of enantiopure starting materials. However, at least some of the enantiopurity is lost in most of the existing reactions used in synthetic organic chemistry. This translates into unnecessary material losses. Naturally enantiopure proteinogenic amino acids that can be transformed into many useful intermediates in drug syntheses, for example, are especially vulnerable to this. The phenylfluoren-9-yl (Pf) group, a relatively rarely used protecting group, has proven to be able to prevent racemization in α-amino compounds. This review article showcases the use of Pf-protected amino acid derivatives in enantiospecific synthesis.
More Related Videos
Related Concept Videos
Diazonium Group Substitution: –OH and –H
Protection of Alcohols
Protection
It defines a protecting group as the masking agent to make the more reactive species inert to a given set of conditions. This concept is depicted via the illustration of liquid flow through different outlets in an assembly of pipes. The analogy helps to understand the role...
Protecting Groups for Aldehydes and Ketones: Introduction
Diazonium Group Substitution with Halogens and Cyanide: Sandmeyer and Schiemann Reactions
Nucleophilic Aromatic Substitution: Addition–Elimination (SNAr)
The reaction begins with an attack of the nucleophile on the carbon that holds the leaving group. This results in the delocalization of the π electrons over the ring carbons. The resonance interaction between the...
Chirality at Nitrogen, Phosphorus, and Sulfur
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...

