The Electrophilic Amination of Organolithium Compounds With Methyllithium-Methoxylamines

Strongly basic aliphatic and benzenoid aromatic organolithium compounds can be stoichiometrically converted to primary amines, upon treatment with two equivalents of a methoxylamine-methyllithium complex, in 14-97% yields, or to secondary amines, either inter- or intramolecularly, upon treatment with one equivalent of a N-alkylmethoxylamine-methyllithium complex, in 30-73% yields. N-Methyl- and N-1-phenylethylmethoxylamines were used to illustrate the intermolecular applications of this methodology, and indoline, isolated as its N-acetyl derivative, was prepared from methyllithium-N-2-(2'-bromophenyl)ethylmethoxylamine in 42% yield, as an illustration of an intramolecular application. A double labelling reaction was done to distinguish between a stepwise or concerted mechanism in these amination reactions using N-methyl-O-(2-bromo)benzylhydroxylamine and N-methyl-d(,1)-O-(2-bromo-(alpha),(alpha)-dideutero)benzylhydroxylamine to provide N-methyl-2-aminobenzyl alcohol, isolated as its N,O-diacetyl derivative, in 13% yield. The deuterium distribution of the latter suggests that amination occurred intermolecularly and is, therefore, sensitive to geometric restraints in this case. This result suggests that electrophilic amination of carbanions with methoxylamine appears to occur via a concerted displacement mechanism, and sets a precedent for the use of a double labelling experiment in mechanistic studies of other systems where traditional probes cannot be used. The amination of methyllithium with either methoxylamine or N,N-dideuteromethoxylamine provides methylamine, isolated as its benzamide derivative, in 33% yield. The possible role of methyllithium, as well as the nature of the active aminating species in aminations with methyllithium-methoxylamines is discussed.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Kokko, Bruce Jerome

• Chemistry, Organic

Identifier

(UMI)AAI8409973

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/70245