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Synthesis of 2-C-Branched Sugars

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posted on 2021-11-12, 14:24 authored by Moore, Peter William

A range of unnatural carbohydrates (sugars) with an unusual 2-C-bromomethylene branch have been synthesised by reaction of the 1,2-cyclopropanated carbohydrate 52 with different nucleophiles. Initial work to optimise the cyclopropane ring opening in the presence of sodium allyloxide/allyl alcohol provided anomers 140 and 141 in up to 75% yield. Use of sodium thiophenolate/thiophenol provided anomeric thioglycosides 181 and 182 (76% yield, 7:2 ratio), while sodium diethylamide/ diethylamine provided anomeric glycosylamines 183 and 184 (50% yield, 1:1 ratio). Further functionalisation of the 2-C-branch of 141 was performed using various palladium-catalysed cross-coupling reactions, providing a series of products. Reaction of 140 and 141 under acidic conditions caused E-Z isomerisation of the bromoalkene forming a single anomer, 194. Efforts to obtain mechanistic information about the cyclopropane ring opening were made through attempted trapping of a cyclopropene intermediate, deuterium labelling experiments, synthesis of possible stable intermediates and reactions with internal nucleophiles.

History

Copyright Date

2012-01-01

Date of Award

2012-01-01

Publisher

Te Herenga Waka—Victoria University of Wellington

Rights License

Author Retains Copyright

Degree Discipline

Chemistry

Degree Grantor

Te Herenga Waka—Victoria University of Wellington

Degree Level

Masters

Degree Name

Master of Science

Victoria University of Wellington Item Type

Awarded Research Masters Thesis

Language

en_NZ

Victoria University of Wellington School

School of Chemical and Physical Sciences

Advisors

Harvey, Joanne