During this project, we reached the aim of establishing synthetic routes to new hydroxamic acid derivatives, which were used as ligands for asymmetric epoxidation of allylic alcohols in water. Three new ligands, (S, R)-3, (S, S)-3 and 14 were successfully synthesized and subsequently tested on standard substrates. To accomplish the ligand synthesis, we used known procedures as well as new ones, for example the coupling of in situ-protected hydroxylamine 5a and activated mixed anhydride 13. As yields were not always satisfying (see Experimental), optimization of several steps could be a general aim for future work, especially considering the synthesis up-scaling of promising ligand 14.
Table of Contents
Acknowledgements
Abbreviations
Table of Contents
1 Introduction
1.1 Sharpless Epoxidation
1.2 Yamamoto-Malkov Epoxidation
1.3 Camphor Derivatives
1.4 Phosphinamides
1.5 Sulfinamides
2 Project Objective
3 Results and Discussion
3.1 Camphor-derived hydroxamic acids
3.1.1 Synthesis of ligands
3.1.2 Application of ligand 3 to vanadium-catalyzed epoxidation
3.2 Hydroxamic acid based on diphenylphosphinamide moiety
3.2.1 Synthesis of ligand
3.2.2 Application of ligand 14 to vanadium-catalyzed epoxidation
3.3 Hydroxamic acids containing sulfinamide moiety
3.3.1 Synthesis of ligand 19 using direct method
3.3.2 Synthesis of ligand 19 using Nosyl protecting group
3.4 Synthesis of #-Benzhydryl-hydroxylamine
4 Conclusions and Future Aspects
4.1 General
4.2 Camphor derivatives
4.3 Sulfinamides
4.4 Phosphinamides
4.5 Anilides
4.6 Binaphthyls
5 Experimental
5.1 General Methods
5.2 Synthesis of hydroxylamine
5.3 Synthesis of Camphor-derived hydroxamic acids
5.3.1 Sulfonamides
5.3.2 Acid chlorides
5.3.3 Hydroxamic acids
5.4 Synthesis of Dpp-derived hydroxamic acid
5.5 Synthesis of sulfinamide-derived amino acid
5.6 Synthesis of #-Nosyl-(R)-phenylglycme
5.7 Epoxidation in water
6 References
- Quote paper
- Dominik Ohlmann (Author), 2007, Novel Hydroxamic Acid-Derived Ligands for Vanadium Catalysed Asymmetric Epoxidations, Munich, GRIN Verlag, https://www.hausarbeiten.de/document/463480
