DEVELOPMENT OF NEW HYPERVALENT IODINE MEDIATED REACTION METHODOLOGIES FOR CLEAVAGE OF ALKENES AND SYNTHESIS OF 1,2,4-OXADIAZOLES.

Author

Jhanvi Sharma, Southern Illinois University CarbondaleFollow

Date of Award

5-1-2014

Degree Name

Master of Science

Department

Chemistry

First Advisor

Hou, Yuqing

Abstract

The first part of thesis describes the synthesis of carbonyl compounds from the styrene and derivatives using [hydroxy(tosyloxy)iodo]benzene, a hypervalent iodine compound, and p-toluenesulfonic acid monohydrate. Four equivalents of hypervalent iodine reagent was necessary to provide the products in high yields. The reaction was performed at 70 °C under argon to avoid further oxidation of benzaldehyde to carboxylic acid. Electron rich styrenes were converted into benzaldehydes in good to high yield, whereas electron deficient styrenes produced bis(tosylates) as the major products. Three paths were possible for the high yield of aldehydes (i) cleavage of glycol intermediate; (ii) cleavage of the epoxide intermediate; (iii) further oxidative cleavage of the rearrangement product - phenylacetaldehydes. The second part of the thesis describes the synthesis of substituted 1,2,4-oxadiazoles from aldoximes. Hypervalent iodine was used at stoichiometric and catalytic level to synthesize 1,2,4-oxadiazoles. The reaction was believed to proceed through nitrile oxide as an intermediate, followed by 1,3-dipolar cycloaddition with nitriles. Moderate yield was obtained when benzonitrile was used, whereas poor yield was obtained with acetonitrile. The possible reason for moderate yield was mainly attributed to two factors: (i) elimination of water molecule from aldoximes; (ii) diastereomeric purity of aldoxime. The study is in preliminary stage and requires further investigation.