Synthesis of heterocycles via isocyanide-based multi-component reactions

This thesis deals with the development of a new multi-component reaction for the synthesis of heterocycles involving the process of insertion of isocyanides into a carbon-palladium bond. The application to the synthesis of oxazolines was explored and was shown to give good yields of 2-aryloxazolines. The reaction conditions developed use a PdCl₂/dppf catalytic system which enables the formation of an amidine intermediate. This intermediate then cyclises into the oxazoline. This reaction was performed on several aromatic systems, electron-rich or electron-poor, and appeared to be very tolerant of substitution pattern. The extension of these conditions to the synthesis of 2-arylbenzoxazoles has been studied. Excellent yields have been obtained for this transformation which suggests that these conditions could be applied to the synthesis of different types of heterocycles. The application to the synthesis of 2-arylbenzothiazoles appeared to be more challenging as a different reactivity was observed. Indeed, the same reaction conditions afforded the unsubstituted benzothiazole. However, a slight modification of the reaction conditions and the use of a copper species as co-catalyst enabled the 2-phenylbenzothiazole to be obtained. This required optimization in order to obtain a good yield for this transformation, and especially to prevent the Ullmann-coupling side-reaction from occuring. A yield of 59% which is noteworthy for a multi-component reaction, was finally obtained for the formation of 2-phenylbenzothiazole.

Name dc:type.qualificationname

mphil

Level dc:type.qualificationlevel

masters-pg

Grantor dc:publisher.institution

University of Strathclyde

Year dc:date.issued

2011

Author dc:creator

• Boissarie, Patrick

DOI

10.48730/6dpv-wd98

Identifier

T13389

OAI identifier oai:identifier

oai:strathclyde:44558d306