The aim of the work is the synthesis of new heterocyclic imines with one or two heteroatoms in the ring and their derivatisation. A sterically uniform chiral 3-thiazoline was synthesised for the first time using a modified Asinger reaction. In the production of derivatives of 3-oxazolines, 3-thiazolines and corresponding six-ring compounds, particular attention is paid to obtaining novel phosphorus compounds with structural similarities to phosphonoamino acids. Furthermore, the diastereoselective and enantioselective addition of various reagents to the reactive C=N double bond is investigated. Methods of enantioselective homogeneous catalysis are also used.

One focus of the work is the production of PNA monomers, which can be of practical importance in the synthesis of hydrolysis-stable DNA analogues. These DNA analogues are currently highly topical in the development of active ingredients for pharmaceuticals and diagnostics.

In addition, efficient methods for the synthesis of racemic alpha- and beta-amino acids and their enantiomer separation are being developed.

Prof. Dr Hiroaki Sasai / Osaka University / Japan

Prof. Dr Masakatsu Shibasaki, University of Tokyo / Japan

Prof. Dr Sabine Köpper / University of Oldenburg

W. Maison, I. Schlemminger, O. Westerhoff, J. Martens: Modified PNAs: A simple method for the synthesis of monomeric building blocks, Biorg. & Med. Chem. Lett. 1999, 9, 581-584 (DOI:10.1016/S0960-894X(99)00024-4)

W. Maison, M. Kosten, A. Charpy, J. Kintscher-Langenhagen, I. Schlemminger, A. Lützen, O. Westerhoff, J. Martens: The Synthesis of Novel Cyclic β-Amino Acids as Intermediates for the Preparation of Bicyclic β-Lactams, Eur. J. Org. Chem. 1999, 2433-2441. (DOI:10.1002/(SICI)1099-0690(199909)1999:9<2433::AID-EJOC2433>3.0.CO;2-X)

O. Westerhoff, J. Martens, C. Thöne: Organometallic Selenolates. 11.- Nucleophilic Substitutions of N-Acyl-4-Chloro-3-Thiazolidines with the Organometallic Selenolates LiSeMcp(CO)₃, M = Mo, W. Crystal Structure of(RS)-3-Acetyl-4-[η⁵-cyclopentadienyl)(tricarbonyl)selenolato-tungsten/II)]-2,2,5,5-tetramethyl-3-thiazolidine, Z. anorg. Allg. Chem. 1999, 625, 1823-1827. (DOI:10.1002/(SICI)1521-3749(199911)625:11<1823::AID-ZAAC1823>3.0.CO;2-A)

W. Maison, A. Lützen, M. Kosten, I. Schlemminger, O. Westerhoff, J. Martens: Synthesis of novel pipecolic acid derivatives: a multicomponent approach from 3,4,5,6-tetrahydropyridines, J. Chem. Soc. Perkin I 1999, 3515-3526. (DOI:10.1039/a905119h)

W. Maison. A. Lützen, M. Kosten, I. Schlemminger, O. Westerhoff, W. Saak, J. Martens: Multicomponent synthesis of tripeptides containing pipecolic acid derivatives: selective induction of cis- and trans-imide bonds into the peptide backbone, J. Chem. Soc. Perkin I 2000, 1867-1871. (DOI:10.1039/b002258f)

I. Schlemminger, Y. Saida, H. Gröger, W. Maison, N. Durot, H. Sasai, M. Shibasaki, J. Martens: Concept of Rigidity: How to Make Enantioselective Hydrophosphonylation of Cyclic Imines Catalyzed by Chiral Heterobimetallic Lanthanoid Complexes almost Perfect, J. Org. Chem. 2000, 65, 4818-4825. (DOI:10.1021/jo991882r)

I. Schlemminger, A. Lützen, A. Willecke, W. Maison, R. Koch, W. Saak, J. Martens: Highly Diastereoselective Hydrophosphonylation of Cyclic Imines using BINOL as Source of Chirality, Tetrahedron Lett. 2000, 41, 7285-7288. (DOI:10.1016/S0040-4039(00)01265-X)

I. Schlemminger, H.-H. Janknecht, W. Maison, W. Saak, J. Martens: Synthesis of the First Enantiomeric Pure 3-Thiazolines via Asinger Reaction, Tetrahedron Lett. 2000, 41, 7289-7292. (DOI:10.1016/S0040-4039(00)01266-1)

W. Maison, I. Schlemminger, O. Westerhoff, J. Martens: Multicomponent Synthesis of Novel Amino Acid Nucleobase Chimeras: a versatile Approach to PNA-Monomers, Biorg. & Med. Chem. 2000, 8, 1343-1360 (DOI:10.1016/S0968-0896(00)00066-3)

N. Graf von Keyserlingk, J. Martens, D. Ostendorf, W. Saak, M. Weidenbruch: Utilisation of industrial waste materials. Part 20: Stereoselective cycloaddition of silylenes and disililene to an enantiomerically pure cyclic ketimine derived from an industrial waste material, J. Chem. Soc. Perkin I 2001, 706-710. (DOI:10.1039/b008708o)

I. Schlemminger, A. Willecke, W. Maison, R. Koch, A. Lützen, J. Martens: Diastereoselective Lewis Acid Mediated Hydrophosphonylation of Heterocyclic Imines: a Stereoselective Approach towards α-Aminophosphonates, J. Chem. Soc. Perkin I 2001, 2804-2816. (DOI:10.1039/b101501j)

N. Graf von Keyserlingk, J. Martens: Synthesis of optically active functionalised cyclic ketimines and their application in enantioselective catalysis, Tetrahedron: Asymmetry 2001, 12, 2213-2222. (DOI:10.1016/S0957-4166(01)00379-2)

N. Graf von Keyserlingk, J. Martens: Highly diastereoselective addition of N-Boc-pyrrolidin-2-yllithium to optically active ketimines: Synthesis of enantiomerically pure 1,3-imidazolidin-2-ones and diamines, Eur. J. Org. Chem. 2002, 301-308. (DOI:10.1002/1099-0690(20021)2002:2<301::AID-EJOC301>3.0.CO;2-Q)

K. Johannes, J. Jakob, M. Hatam, J. Martens: Synthesis of β-Oxabutyrolactams starting from 2,5-Dihydrooxazoles, Synthesis 2009, 3279-3284. (DOI:10.1055/s-0029-1216959)

K. Johannes, J. Martens: Synthesis of different types of valerolactams starting from 2,5-dihydrooxazoles, Tetrahedron 2010, 66, 242-250. (DOI:10.1016/j.tet.2009.10.107)

K. Schulz, L. Ratjen: Homo- and heterogeneous: enantioselective Mannich addition of ketones to endocyclic carbon-nitrogen double bonds, Tetrahedron 2011, 67, 546-553. (DOI:10.1016/j.tet.2010.10.079)