Synlett 2009(18): 2896-2912  
DOI: 10.1055/s-0029-1218021
ACCOUNT
© Georg Thieme Verlag Stuttgart ˙ New York

Palladium-Catalyzed Alkynylation of Aryl and Hetaryl Halides: A Journey from Conventional Palladium Complexes or Salts to Palladium/Carbon

Manojit Pal*,
New Drug Discovery, Matrix Laboratories Limited, Anrich Industrial Estate, Bollaram, Jinnaram Mandal, Medak District, 502325 Andhra Pradesh, India
e-Mail: manojitpal@rediffmail.com;
Further Information

Publication History

Received 26 March 2009
Publication Date:
15 September 2009 (online)

Abstract

Palladium-catalyzed alkynylation of aryl and hetaryl ­halides has found wide application in the areas of synthetic, heterocyclic, and medicinal chemistry. Attempts to introduce the stable and potentially recyclable palladium/carbon has provided an attractive alternative to the homogeneous palladium catalytic process. The present article provides a personal account of the outcome of the use of conventional palladium catalysts versus palladium/carbon, especially under Sonogashira conditions.

1 Introduction

1.1 The Focus on Palladium/Carbon

1.2 The Origin of the Research

2 Copper-Free Sonogashira Coupling: An Unusual Observation

3 Palladium-Mediated Synthesis of 3-Substituted (Thio)flavones: The Role of (S)-Prolinol and Copper

4 Palladium/Carbon in Water

4.1 Synthesis of Benzo[b]furans

4.2 2-Aminoethanol as an Alternative Base: Synthesis of Aryl- and Hetaryl-Substituted Alkynes

4.3 Synthesis of Indoles

5 Palladium/Carbon in Organic Solvents

5.1 Synthesis of Isocoumarins and Phthalides

5.2 Synthesis of Thieno[2,3-c]pyranones

5.3 Synthesis of Alkynylpyrimidines

5.4 Synthesis of Furoquinolines and Pyrroloquinolines

5.5 Synthesis of 2H-1,2-Benzothiazine 1,1-Dioxides

6 Alkynylation of b-Chloroacroleins

7 Synthesis of Substituted Benzenes Fused with Carbocycles/Heterocycles: Palladium Salts versus Palladium/Carbon

8 Palladium/Carbon in the Union of Organic Azide and Terminal Alkynes

9 Conclusions: Towards Fulfilling the Requirements for Commercialization

1

Present address: Institute of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad 500046, Andhra Pradesh, India; Fax +914066571581.