Related Experiment Video
Updated: Feb 22, 2026

A Direct, Early Stage Guanidinylation Protocol for the Synthesis of Complex Aminoguanidine-containing Natural Products
Published on: September 9, 2016
Asymmetric Total Synthesis of Gracilamine and Determination of Its Absolute Configuration
Xiao-Dong Zuo1, Shu-Min Guo1, Rui Yang1
1State Key Laboratory and Institute of Elemento-organic Chemistry, College of Chemistry, Nankai University , Tianjin 300071, China.
Abstract:
(+)-Gracilamine, a biologically attractive and structurally unique pentacyclic Amaryllidaceae alkaloid, was biomimetically synthesized in 11 linear steps in 9.9% overall yield from the known racemic oxocrinine. The synthesis features an asymmetric hydrogenation, a ring-opening/benzylic oxidation/cyclization sequence, and a biomimetic intramolecular cycloaddition. This total synthesis not only allows the assignment of its absolute configuration, but also provides experimental support for the hypothesis that naturally occurring (+)-gracilamine is biogenetically derived from the crinine-type alkaloid (+)-epivittatine.
Related Concept Videos
Preparation of 1° Amines: Hofmann and Curtius Rearrangement Overview
Preparation of Carboxylic Acids: Carboxylation of Grignard Reagents
Preparation of 1° Amines: Hofmann and Curtius Rearrangement Mechanism
Preparation of 1° Amines: Gabriel Synthesis
Strong bases like NaOH or KOH deprotonate the phthalimide to form the corresponding anion, which acts as a nucleophile. Further, the anion attacks an...
Prochirality
Racemic Mixtures and the Resolution of Enantiomers

