@article{DzambaskiMarkovicKleinpeteretal.2013,
  author    = {Dzambaski, Zdravko and Markovic, Rade and Kleinpeter, Erich and Baranac-Stojanovic, Marija},
  title     = {2-Alkylidene-4-oxothiazolidine S-oxides - synthesis and stereochemistry},
  series = {Tetrahedron},
  volume    = {69},
  journal   = {Tetrahedron},
  number    = {31},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0040-4020},
  doi       = {10.1016/j.tet.2013.05.087},
  pages     = {6436 -- 6447},
  year      = {2013},
  abstract  = {A series of 5-unsubstituted and 5-substituted 2-alkylidene-4-oxothiazolidine-S-oxides were synthesized by the sulfur-oxidation with m-CPBA. The stereochemistry of 5-substituted sulfoxides was determined by means of NMR spectroscopy and DFT theoretical calculations. It was found that the thermodynamically less stable anti-isomer was initially formed in the course of the oxidation, but it underwent epimerization to the mixture enriched in the more stable syn-isomer, during the work-up process. The higher stability of syn-isomers is ascribed to the stronger hyperconjugative sigma(C-H)->sigma*(S-O) interaction versus the weaker sigma(C-C)->sigma*(S-O) delocalization in their anti-counterparts and to the existence of intramolecular 1,5-CH center dot center dot center dot C hydrogen bonds.},
  language  = {en}
}
@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}
}