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02:44Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
Alkenes are converted to 1,2-diols or glycols through a process called dihydroxylation. It involves the addition of two hydroxyl groups across the double bond with two different stereochemical approaches, namely anti and syn. Dihydroxylation using osmium tetroxide progresses with syn stereochemistry.
01:14Alkylation of β-Diester Enolates: Malonic Ester Synthesis
Malonic ester synthesis is a method to obtain α substituted carboxylic acids from ꞵ-diesters such as diethyl malonate and alkyl halides.
01:27Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation
Robinson annulation is a base-catalyzed reaction for the synthesis of 2-cyclohexenone derivatives from 1,3-dicarbonyl donors (such as cyclic diketones, β-ketoesters, or β-diketones) and α,β-unsaturated carbonyl acceptors. Named after Sir Robert Robinson, who discovered it, this reaction yields a six-membered ring with three new C–C bonds (two σ bonds and one π bond).
02:34Preparation of Alkynes: Dehydrohalogenation
Introduction
Alkynes can be prepared by dehydrohalogenation of vicinal or geminal dihalides in the presence of a strong base like sodium amide in liquid ammonia. The reaction proceeds with the loss of two equivalents of hydrogen halide (HX) via two successive E2 elimination reactions.
Alkynes can be prepared by dehydrohalogenation of vicinal or geminal dihalides in the presence of a strong base like sodium amide in liquid ammonia. The reaction proceeds with the loss of two equivalents of hydrogen halide (HX) via two successive E2 elimination reactions.
01:57Preparation of Diols and Pinacol Rearrangement
Compounds bearing two hydroxyl groups are known as diols. When the hydroxyl groups are located on adjacent carbon atoms, the diols are called vicinal diols or glycols. Under acidic conditions, vicinal diols undergo a specific reaction called pinacol rearrangement.
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
01:32Aldehydes and Ketones with HCN: Cyanohydrin Formation Overview
Cyanohydrins are compounds that contain –CN and –OH groups on the same carbon atom. They are formed by the nucleophilic addition of the cyanide ions to the carbonyl group. Cyanide ions are highly basic and nucleophilic and can be generated from HCN under aqueous conditions. However, since HCN is a weak acid, the number of cyanide ions generated is very small. Hence, a small amount of base or KCN/NaCN is added to HCN to increase the concentration of the cyanide ions in the reaction mixture.
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Updated: Jun 4, 2026
06:18
Syntheses, Crystallization, and Spectroscopic Characterization of 3,5-Lutidine N-Oxide Dehydrate
Published on: April 24, 2018
Synthesis of (±)-7-hydroxylycopodine.
1Department of Chemistry, Brandeis University, Waltham, Massachusetts 02454-9110, USA.
Organic Letters
|January 29, 2011
Summary
A six-step synthesis successfully produced (±)-7-hydroxylycopodine. The key Prins cyclization step efficiently formed a complex tricyclic structure from a bicyclic precursor.
Area of Science:
- Organic Chemistry
- Synthetic Chemistry
- Natural Product Synthesis
Background:
- Lycopocodine alkaloids are a significant class of natural products with diverse biological activities.
- The total synthesis of complex alkaloids like (±)-7-hydroxylycopodine presents a considerable challenge in organic chemistry.
Purpose of the Study:
- To develop an efficient synthetic route to (±)-7-hydroxylycopodine.
- To explore novel synthetic methodologies for constructing the lycopocodine core structure.
Main Methods:
- A six-step synthetic sequence was designed and executed.
- The key step involved a Prins cyclization reaction of a bicyclic keto alkyne using concentrated sulfuric acid (H2SO4).
Main Results:
Conclusions:
- A viable six-step synthetic pathway to (±)-7-hydroxylycopodine has been established.
- The Prins cyclization is a powerful tool for constructing complex polycyclic systems relevant to alkaloid synthesis.