Palladium Catalyzed Direct C-H Arylation of Heteroarenes Using Aryl Chloride Coupling Partner

Ahmed, Jasimuddin (2015) Palladium Catalyzed Direct C-H Arylation of Heteroarenes Using Aryl Chloride Coupling Partner. Masters thesis, Indian Institute of Science Education and Research Kolkata.

PDF (MS dissertation of Jasimuddin Ahmed (13IP002)) Jasimuddin-13IP002.pdf - Submitted Version Restricted to Repository staff only Download (1MB)

Abstract

This thesis covers a general study on the Arylation of Heteroarenes mainly using palladium catalyst. The first part of the work covered introduction, historical background and importance of this work. The drawbacks of the previous work and how can we proceed taking these drawbacks as challenge, is discussed in the second part. Arylation of heteroarenes has received considerable attention in the last decade as a, very important process to yield arylated heteroarenes, which have enormous application in medicinal chemistry and material science. From our work, it can be observed that our catalytic condition is able to afford the arylated heteroarenes compounds of 1-methylpyrrole, 1-methylindole, furan and thiophene resulting only mono-substituted product. Thus the catalyst is quite versatile in terms of its activity towards a number of different variety of heteroarenes. Moreover, the catalyst can work under low catalyst loading condition (0.5 mol%). Furthermore, it was observed that the present catalytic condition can sustain the formyl group, which is considered as a challenging task in this field of coupling chemistry. It was further established that the catalyst can perform C-3 position arylation when the C-2 position of the heteroarene is blocked with almost equal efficiency as that of C-2 arylation. All these reactions has been performed without using any kind of additive and using more challenging aryl chlorides as coupling partners which are cheaper compared to commonly used aryl iodide and aryl bromide coupling partners.. We found the catalyst can stay alive for a consecutive catalytic cycles and it does not loose any efficiency upto three consecutive catalytic cycles. This prompted us to try the catalyst for consecutive arylation study in the same reaction pot. We are currently exploring the synthesis of pharmaceutically important molecules in a more cost effective route applying this catalytic protocol.

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