Recent Advances on Nazarov Cyclization PPT. Examples of asymmetric Nazarov Cyclization are covered in this slide. To Know more visit - https://chemistry-name-reaction.com/

1. Avishek Das (1810204)
PhD Student
Department of Chemistry
IISER Bhopal
Recent Advances on Nazarov Cyclizations
https://chemistry-name-reaction.com/
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2. Outline
Introduction
Asymmetric Nazarov Cyclizations
 Chiral Auxiliary
 Lewis Acid Catalysis
 Organocatalysis

3. 4p conrotatory electrocyclization
Efficient tool to access cyclopentenones with excellent stereochemical control
Various techniques (Chiral auxiliary approach,Organocatalysis etc.) have been
developed to achieve enantioselectivity
Earliest Catalytic
Asymmetric
4p Electrocyclization
Ivan Nazarov
3
Nazarov Cyclization - An Overview

4. Jones and co-workers J. Am. Chem. Soc. 1982, 104, 2642 4
Asymmetric Nazarov with a Silicon Chiral Auxiliary
Stereochemical Model

5. 5
Asymmetric Nazarov with Chiral Auxiliary on the Allene
Tius and co-workers Org. Lett. 2000, 2, 2447

6. R1 R2 yield (%) ee (%)
Me Me 35 03
Ph Me 86 42
Me Ph 73 76
Ph Ph 98 86
Stereochemical Model
6
Lewis Acid Mediated Asymmetric Nazarov Cyclizations
Aggarwal and co-workers Org. Lett. 2003, 5, 5075

7. R
equiv of
Lewis Acid
yield (%) ee (%)
Ph 1.0 92 86
Ph 0.5 56 87
Me 1.0 72 84
Me 0.5 56 85
Stereochemical Model
7
Lewis Acid Mediated Asymmetric Nazarov Cyclizations
Aggarwal and co-workers Org. Lett. 2003, 5, 5075

8. Entry Solvent T (°C) Yield(%) ee (%)
1 CH2Cl2 rt 84 86
2 CH2Cl2 40 79 85
3 Cl(CH2)2Cl 60 91 60
4 THF rt 31 82
5 Toluene rt 44 76
6 MeCN rt - -
8
Ni(II)-Catalyzed Enantioselective Nazarov Cyclizations
Togni and co-workers Chem. Commun. 2008, 4315

9. Stereochemical Model
9
Cr(III)-Salen Catalyzed Enantioselective Nazarov Cyclizations
Rawal and co-workers J. Am. Chem. Soc. 2013, 135, 4988

10. 10
Chiral-at-Metal Complex Catalyzed Asymmetric Nazarov
Cyclizations
Meggers and co-workers Adv. Synth. Catal. 2018, 360, 2093

11. 11
Chiral-at-Metal Complex Catalysed Asymmetric Nazarov
Cyclizations

12. 12
Organocatalytic Asymmetric Nazarov Cyclizations
Tius and co-workers J. Am. Chem. Soc. 2010, 132, 8266
Tius and co-workers Org. Lett. 2010, 12, 440

13. 13
Chiral Brønsted Acid Catalyzed Asymmetric Nazarov Cyclizations
Tius and co-workers Angew. Chem., Int. Ed. 2014, 53, 6180

14. 14
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