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Title: Studies on the heterocyclisation reactions of isocyanides and isocyanide dihalides
Author: Currie, Kevin Somerville
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1993
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This thesis is concerned with the synthesis of five-, six-, seven-, and eight-membered heterocycles by the cyclisation reactions of isocyanides and isocyanide dihalides, and the chemical manipulation of the products so obtained. The Lewis acid promoted cyclisation reactions of 2-phenoxyphenyl and 2-phenylthiophenyl isocyanide derivatives gave the corresponding C-11 unsubstituted dibenz[b,f][1,4]oxazepine and dibenzo[b,f][1,4]thiazepine derivatives. Further investigations of this reaction demonstrated that the nature of the Lewis acid and the presence and nature of substituents in the isocyanide substrate were critical factors in determining the success of the reaction. In contrast the Lewis acid promoted cyclisation reactions of isocyanides with carbon-carbon double bonds, in the case of cis and trans-2-(2-phenylethenyl)phenyl isocyanides and 2-(1-phenylprop-1-en-3-yl)oxphenyl isocyanide were found to be unsuccessful. The ability of isocyanide dihalides to undergo intramolecular Lewis acid promoted heterocyclisation reactions was also investigated. Such reactions of 2-phenoxy-, 2-phenylthio-, 2-phenylamino-, and 2-benzylphenyl isocyanide derivatives, and of 2-phenoxy- and 2-phenylthiopyridinyl isocyanide dihalides were found to provide an extremely useful and high yielding synthetic route to the corresponding halogenated tricyclic heteropines. The nucleophilic displacement reactions of these halogenated products were also briefly investigated. It was also shown that six-membered heterocycles could be prepared by the Lewis acid promoted cyclisation of 1,1'-biphenyl-2-isocyanides and 1,1'-biphenyl-2-isocyanide dihalides, to give a variety of phenanthridine derivatives. The formation of six-membered rings by the Lewis acid promoted cyclisation of heteroaromatic isocyanide dihalides was also investigated. In addition, it was shown that dibenz[b,f]azocine derivatives could be obtained by the Lewis acid promoted cyclisation reactions of cis-2-(2-phenylethenyl)phenyl isocyanide dichloride and 2-(2-phenylethyl)phenyl isocyanide dihalides. The Lewis acid prompted reactions of some alkyl isocyanides and isocyanide dihalides in the case of 3-methoxybenzyl isocyanide and 2-phenylethyl isocyanide were examined and were found to be largely unsuccessful.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available