Title

Tellurium-triggered reactions of 5-hydroxymethyl-2-oxazolidinone tosylates, aziridinemethanol tosylates, and oxiranemethanol tosylates: Synthesis of allylic amines and no-solvent synthesis of allylic alcohols via ultrasound and microwave irradiations

Date of Award

1999

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Advisor(s)

Donald C. Dittmer

Keywords

Tellurium-triggered, Aziridinemethanol tosylates, Oxiranemethanol tosylates, Allylic amines, Ultrasound, Microwave irradiations

Subject Categories

Chemistry | Organic Chemistry | Physical Sciences and Mathematics

Abstract

A novel methodology for the stereospecific syntheses of allylic amines from 5-hydroxymethyl 2-oxazolidinone tosylates via tellurium chemistry has been discovered. These are the first reactions between 5-hydroxymethyl 2-oxazolldinone tosylates and telluride ions. Compared with other procedures, the advantages of this method include (1) The use of mild temperatures (room temperature), (2) oxazolidinones; are readily available from aminodiols (derived from allylic alcohols), and triphosgene, methyl chloroformate, and dimethyl carbonate, (3) either enantiomer of the non-racemic allylic amine can be obtained since the starting enantiomeric oxiranernethanols are available via Sharpless asymmetric epoxidation of allylic alcohols, (4) the problem of regioselectivity in the telluride reaction that is observed with some aziridinemethanol derivatives reported previously was avoided in this process.

Tellurium-mediated nucleophilic reduction under "no-solvent" conditions via ultrasound and microwave irradiation has been investigated systematically. Secondary and tertiary allylic alcohols were synthesized with different substitution patterns by "no-solvent" reactions in excellent yields. Compared with the use of a mortar and pestle, the use of ultrasound and microwave has the following advantages: (1) The "no-solvent" synthesis of allylic alcohols is an environmentally benign organic reaction, which excludes the usage of non-environmentally friendly organic solvent, (2) more efficient and much more convenient, (3) avoid the contact of chemicals with personnel that the trituration process involved, (4) the yields of all the "no-solvent" reactions are from good to excellent.

An improved phase transfer system was discovered by changing the reducing agent in the aqueous phase. Rongalite and sodium hydroxide (NaOH) were replaced by NaBH 4 to reduce the elemental tellurium to telluride ions. The advantage of this new system is that the potential problem of decomposition of the phase transfer catalyst under basic conditions can be avoided.

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