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A Direct, Early Stage Guanidinylation Protocol for the Synthesis of Complex Aminoguanidine-containing Natural Products
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A Guide to Directing Group Removal: 8-Aminoquinoline
Liam S Fitzgerald1, Miriam L O'Duill2
1School of Chemistry, National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|February 9, 2021
Summary
Removing directing groups after transition metal catalysis is challenging. This review critically examines strategies for removing 8-aminoquinoline directing groups, offering solutions for difficult substrates.
Area of Science:
- Organic Chemistry
- Catalysis
- Synthetic Methodology
Background:
- Directing groups enhance selectivity in transition metal catalysis.
- Efficient removal of directing groups post-functionalization remains a significant synthetic challenge.
- 8-aminoquinoline is a widely employed N,N-bidentate directing group.
Purpose of the Study:
- To critically review strategies for removing 8-aminoquinoline directing groups.
- To identify limitations of existing removal methods.
- To propose alternative approaches for challenging substrates.
Main Methods:
- Literature review of 8-aminoquinoline directing group removal strategies (2005-2020).
- Analysis of the scope and limitations of reported methods.
- Identification of substrate-dependent challenges.
Main Results:
- Existing methods for 8-aminoquinoline removal have limitations.
- Certain substrate classes present significant challenges for auxiliary removal.
- A critical overview of successful and unsuccessful strategies is presented.
Conclusions:
- Developing robust methods for directing group removal is crucial for synthetic efficiency.
- Alternative strategies are needed for removing 8-aminoquinoline from complex molecules.
- This review serves as a guide for chemists utilizing directing group strategies.
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