Related Experiment Video
Updated: Jul 3, 2026

Enzymatic Cascade Reactions for the Synthesis of Chiral Amino Alcohols from L-lysine
Published on: February 16, 2018
Enantiospecific synthesis of (+)-alstonisine via a stereospecific osmylation process
Jie Yang1, Xiangyu Z Wearing, Philip W Le Quesne
1Department of Chemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, USA.
Abstract:
The first enantiospecific total synthesis of (+)-alstonisine has been accomplished from D-tryptophan methyl ester 13 in 12% overall yield (in 17 reaction vessels). A diastereospecific osmylation process has been employed as a key step to convert indole 18 into spirocyclic oxindole 19. Mechanistic studies of the stereoselective osmylation of the 2,3-indole double bond of indole alkaloids has been carried out. Compelling evidence for the intramolecular delivery of OsO4 via N b-complexation was obtained for the osmylation process. The correct structure of (+)-alstonisine (1) was determined by NOE spectroscopic experiments and further confirmed by single-crystal X-ray analysis.
Related Concept Videos
Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
α-Alkylation of Ketones via Enolate Ions
Alkylation of β-Diester Enolates: Malonic Ester Synthesis
Alkylation of β-Ketoester Enolates: Acetoacetic Ester Synthesis
Synthesis of α-Substituted Carbonyl Compounds: The Stork Enamine Reaction
Preparation of Alkynes: Alkylation Reaction
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.

