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Cover Picture (Angew. Chem. Int. Ed. Engl. 23/24/1996)
Publication year - 1996
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Reports
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.199626891
Subject(s) - stereocenter , cover (algebra) , center (category theory) , chirality (physics) , stereochemistry , chemistry , enantiomer , physics , crystallography , enantioselective synthesis , organic chemistry , mechanical engineering , chiral symmetry breaking , quantum mechanics , quark , nambu–jona lasinio model , catalysis , engineering
The cover picture shows the principle of the “Self‐Regeneration of Stereocenters (SRS)”, a synthetic method in which a stereogenic center is temporarily destroyed with formation of an intermediate having a trigonal center. A subsequent diastereoselective reaction results in the formation of the stereogenic center once more. The additional center of chirality essential for the diastereoselective reaction is generated by acetalization (with an aldehyde) of the functional groups X and Y in the chiral starting material. The reaction sequence leads to a dissociative, enantioselecitve substitution at a single stereogenic center in a chiral compound without the use of a chiral auxiliary—hence the name “self‐regeneration”. The general formula of typical glycine derivatives is shown in yellow in the center of the scheme. These are easily prepared in enantiomerically pure form by resolution of the appropriate racemate and have been shown to be particularly useful for the synthesis of α,α‐disubstituted amino acids. As these compounds are prepared from chiral starting materials, they also represent the abandonment of the synthetic principle. D. Seebach et al. report more on SRS on p. 2708 ff.