Synthesis of Highly Functionalized Pyrroles Using a Dirhodium Catalyst Público

Abstract

Pyrroles are common structural motifs in natural compounds, which, in recent years, have called for an increased demand of new methods for their synthesis. The conversion of furan to highly functionalized pyrroles was investigated using a dirhodium catalyst. It was found that in the presence of an N-sulfonyltriazoles, a formal [3+2] cycloaddition occurred to produced bicyclic hemiaminals which ring opened, resulting in pyrrole product. This study focused primarily on expanding the scope of this reaction in terms of variation of the N-sulfonyl protecting group and substituents on the triazole compound. In comparison to other synthetic methods, this synthesis utilizes mild reaction conditions and inexpensive, shelf-stable starting materials.

Table of Contents

Table of Contents Page

Introduction...................................................1

New Approach to Pyrrole Synthesis....................11

Lewis Acid Exploration.....................................14

Heterocycle Exploration...................................16

Furan Exploration...........................................19

Triazole Synthesis..........................................21

Discussion/Conclusion.....................................26

Experimental Data..........................................31

Figure Page

1. Structure of Rh2(S-DOSP)4...........................11

Tables

1. Catalyst and Solvent Screening.....................12

2. Exploration of Chiral Catalysts......................14

3. Lewis Acid Screening..................................15

4. Heterocycle Scope Exploration......................17

5. 2,5-Disubstituted Furan Scope.......................20

6. Ethanesulfonyl Substrate Scope.....................22

7. Triazole Substrate Scope..............................25

Schemes

1. Pd-Catalyzed Pyrrole Formation....................................................................3

2. 4-pi-electrocyclization synthesis of pyrroles.....................................................4

3. Copper and Rhodium catalyzed formation of disubstituted indolizines....................7

4. Ring-opened diene product through zwitterionic intermediate...............................9

5. Mechanism of 8-oxabicyclo[3.2.1]octadiene formation........................................10

6. Proposed mechanism for pyrrole formation.......................................................26

7. Proposed cyclopropanation mechanism for pyrrole formation...............................27

About this Honors Thesis

Rights statement

• Permission granted by the author to include this thesis or dissertation in this repository. All rights reserved by the author. Please contact the author for information regarding the reproduction and use of this thesis or dissertation.

School	Emory College
Department	Chemistry
Degree	BS
Submission	Honors Thesis
Language	English
Research Field	Chemistry, Organic
Palavra-chave	Organic Synthesis
Committee Chair / Thesis Advisor	Davies, Huw, Emory University
Committee Members	Moore, Judy Raggi, Emory University Soria, Jose, Emory University

Última modificação

Primary PDF

Thumbnail	Title	Date Uploaded	Actions
	Synthesis of Highly Functionalized Pyrroles Using a Dirhodium Catalyst ()	2018-08-28 12:53:58 -0400	Press to Select an action Download

Supplemental Files

Thumbnail	Title	Date Uploaded	Actions