Abstract
The configuration at a stereogenic nitrogen center (SNC) determines the spatial organization
of a molecule as do stereogenic carbon centers or other stereochemical moieties. The
contributions of SNCs to molecular function and their consideration in molecular design
are rarely prominently presented. Underlying is the configurational lability of SNCs
with a free electron pair and the scarcity of methods for the stereoselective synthesis
of compounds with SNCs in general. In this review, we discuss methods to access compounds
with configurationally stable SNCs and highlight some of the synthetically most relevant
applications. We hope to draw attention to the potential of this stereochemical feature
that can be present in diverse compounds such as N-oxides, oxaziridines, haloamines,
ammonium ions, metal-bound amines, and constrained amines and amides.
1 Introduction
2 Some Historical Notes
3 Factors That Influence The Nitrogen Inversion Barrier
4 Preparation and Isolation of Compounds with Configurationally Stable Stereogenic
Nitrogen Centers
5 Selected Applications of Compounds with Stereogenic Nitrogen Centers
6 Final Remarks
Key words
stereoselective synthesis - nitrogen - chirality - cations - amines - N-oxides