@article{KruegerKellingSchildeetal.2016,
  author    = {Kr{\"u}ger, Tobias and Kelling, Alexandra and Schilde, Uwe and Linker, Torsten},
  title     = {Simple Synthesis of gamma-Spirolactams by Birch Reduction of Benzoic Acids},
  series = {European journal of organic chemistry},
  journal   = {European journal of organic chemistry},
  number    = {6},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1434-193X},
  doi       = {10.1002/ejoc.201601650},
  pages     = {1074 -- 1077},
  year      = {2016},
  abstract  = {A convenient synthesis of gamma-spirolactams in only two steps was developed. Birch reduction of benzoic acids and immediate alkylation with chloroacetonitrile afforded cyclohexadienes in high yields. The products could be isolated by crystallization on a large scale in analytically pure form. Subsequent hydrogenation with platinum(IV) oxide as the catalyst reduced the nitrile functionality and the double bonds in the same step with excellent stereoselectivity. The relative configurations were determined unequivocally by X-ray analyses. Direct cyclization of the intermediary formed amino acids afforded the desired gamma-spirolactams in excellent overall yields. The procedure is characterized by few steps, cheap reagents, and can be performed on a large scale, interesting for industrial processes.},
  language  = {en}
}
@article{KruegerKellingLinkeretal.2019,
  author    = {Krueger, Tobias and Kelling, Alexandra and Linker, Torsten and Schilde, Uwe},
  title     = {Crystal structures of three cyclohexane‑based γ‑spirolactams},
  series = {BMC Chemistry},
  volume    = {13},
  journal   = {BMC Chemistry},
  number    = {69},
  publisher = {Springer International Publishing},
  address   = {Basel},
  issn      = {2661-801X},
  doi       = {10.1186/s13065-019-0586-7},
  pages     = {9},
  year      = {2019},
  abstract  = {The title compounds, 2-azaspiro[4.5]deca-1-one, C₉H₁₅NO, (1a), cis-8-methyl-2-azaspiro[4.5]deca-1-one, C₁₀H₁₇NO, (1b), and trans-8-methyl-2-azaspiro[4.5]deca-1-one, C₁₀H₁₇NO, (1c), were synthesized from benzoic acids 2 in only 3 steps in high yields. Crystallization from n-hexane afforded single crystals, suitable for X-ray diffraction. Thus, the configurations, conformations, and interesting crystal packing effects have been determined unequivocally. The bicyclic skeleton consists of a lactam ring, attached by a spiro junction to a cyclohexane ring. The lactam ring adopts an envelope conformation and the cyclohexane ring has a chair conformation. The main difference between compound 1b and compound 1c is the position of the carbonyl group on the 2-pyrrolidine ring with respect to the methyl group on the 8-position of the cyclohexane ring, which is cis (1b) or trans (1c). A remarkable feature of all three compounds is the existence of a mirror plane within the molecule. Given that all compounds crystallize in centrosymmetric space groups, the packing always contains interesting enantiomer-like pairs. Finally, the structures are stabilized by intermolecular N-H···O hydrogen bonds.},
  language  = {en}
}
@misc{KruegerKellingLinkeretal.2019,
  author    = {Krueger, Tobias and Kelling, Alexandra and Linker, Torsten and Schilde, Uwe},
  title     = {Crystal structures of three cyclohexane‑based γ‑spirolactams},
  series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe},
  number    = {738},
  doi       = {10.25932/publishup-43491},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-434911},
  pages     = {9},
  year      = {2019},
  abstract  = {The title compounds, 2-azaspiro[4.5]deca-1-one, C₉H₁₅NO, (1a), cis-8-methyl-2-azaspiro[4.5]deca-1-one, C₁₀H₁₇NO, (1b), and trans-8-methyl-2-azaspiro[4.5]deca-1-one, C₁₀H₁₇NO, (1c), were synthesized from benzoic acids 2 in only 3 steps in high yields. Crystallization from n-hexane afforded single crystals, suitable for X-ray diffraction. Thus, the configurations, conformations, and interesting crystal packing effects have been determined unequivocally. The bicyclic skeleton consists of a lactam ring, attached by a spiro junction to a cyclohexane ring. The lactam ring adopts an envelope conformation and the cyclohexane ring has a chair conformation. The main difference between compound 1b and compound 1c is the position of the carbonyl group on the 2-pyrrolidine ring with respect to the methyl group on the 8-position of the cyclohexane ring, which is cis (1b) or trans (1c). A remarkable feature of all three compounds is the existence of a mirror plane within the molecule. Given that all compounds crystallize in centrosymmetric space groups, the packing always contains interesting enantiomer-like pairs. Finally, the structures are stabilized by intermolecular N-H···O hydrogen bonds.},
  language  = {en}
}
@article{SchmidtStaudeKellingetal.2011,
  author    = {Schmidt, Bernd and Staude, Lucia and Kelling, Alexandra and Schilde, Uwe},
  title     = {A Cross-Metathesis-Conjugate addition route to enantiopure gamma-Butyrolactams and gamma-Lactones from a C-2-Symmetric Precursor},
  series = {European journal of organic chemistry},
  journal   = {European journal of organic chemistry},
  number    = {9},
  publisher = {Wiley-Blackwell},
  address   = {Malden},
  issn      = {1434-193X},
  doi       = {10.1002/ejoc.201001528},
  pages     = {1721 -- 1727},
  year      = {2011},
  abstract  = {A protected derivative of (3R, 4R)-hexa-1,5-diene-3,4-diol, a conveniently accessible C-2-symmetric building block, undergoes single or double cross metathesis with methyl acryl-ate. The cross metathesis products are amenable to stereoselective conjugate addition reactions and can be converted into either gamma-butyrolactones or gamma-lactams.},
  language  = {en}
}