Asymmetric catalytic Mannich-type reactions in enantioselective synthesis of beta-amino acids

Thumbnail Image

URL

Journal Title

Journal ISSN

Volume Title

Helsinki University of Technology | Master's thesis
Checking the digitized thesis and permission for publishing
Instructions for the author
Location:
P1 Ark TKK

Authors

Date

2003

Department

Kemian tekniikan osasto

Major/Subject

Orgaaninen kemia

Mcode

Kem-4

Degree programme

Language

en

Pages

71+14

Series

Abstract

In the literature survey applications and the use of beta-amino acids are introduced. Different methods to synthesize beta-amino acids are also discussed. The literature survey also includes a section where characteristics of 9-bromo-9-phenylfluorene and its use are introduced. The objective of the research was to synthesize beta-amino acids through a Mannich-type reaction. The aim of this project was to study, whether a bulky protective group on nitrogen has an effect on the stereo selectivity of the reaction in the synthesis of beta-amino acids. 9-Bromo-9-phenylfluorene is a large protecting group for nitrogen protection. It is stable and rigid steric bulky group. The protection reaction was straightforward as was the cleavage of this protecting group from the final product. The experimental part of the study began with synthesizing the starting materials for the Mannich-type reaction. Silyl ketene acetal and imine compounds were the starting materials that needed to be synthesized. The imine compound contained the bulky 9phenylfluorene group. This imine compound, benzylidene-(9-phenyl-9-fluorenyl) imine, was prepared starting from 9-bromo-9-phenylfluorene, with a new method, developed during this research. The Mannich-type reaction between silyl ketene acetal and benzylidene-(9-phenyl-9-fluorenyl) imine did not proceed as desired. Also, the reaction between a Reformatsky reagent and benzylidene-(9-phenyl-9-fluorenyl) imine was not successful. These results indicate that the imine compound is too bulky. The 9phenylfluorene group hinders the attack of the silyl ketene acetal and Reformatsky reagent so effectively that no reaction takes place. If this imine had a reactive group on the other end, it could be quite freely manipulated, because this other protected end of the imine survives many types of reactions.

Description

Supervisor

Koskinen, Ari

Thesis advisor

Castillo, Joel

Keywords

Other note

Citation

Permanent link to this item

https://urn.fi/URN:NBN:fi:aalto-2020120450154

Collections

[dipl] Teknillinen korkeakoulu / TKK