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Spectroscopic Characterization of 1‐Naphthyl Isocyanate Anion Radical and of Tris(1‐naphthyl) Isocyanurate Atropisomers
Author(s) -
Peters Steven J.,
Kassabaum Mark E.,
Nocella Michael K.,
McDonald Robert
Publication year - 2015
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201500863
Subject(s) - chemistry , diastereomer , atropisomer , isocyanate , steric effects , monoclinic crystal system , moiety , substituent , tris , nuclear magnetic resonance spectroscopy , polymer chemistry , medicinal chemistry , crystal structure , stereochemistry , crystallography , organic chemistry , biochemistry , polyurethane
Room‐temperature potassium metal reduction of 1‐naphthyl isocyanate in THF results in a rapid cyclotrimerization (initiated by the 1‐naphthyl isocyanate anion radical) that generates two diastereoisomers (atropisomers) of tris(1‐naphthyl) isocyanurate. The formation of the syn and anti diastereoisomers was monitored by 1 H and 13 C NMR spectroscopy. Upon completion of the cyclotrimerization, the two diastereoisomers were isolated, and their configuration was assigned by NMR spectroscopy. Both compounds crystallize in the monoclinic C 2/ c space group, and single‐crystal X‐ray diffraction analyses confirm the structures of both isomeric forms. The results from this study prove that alkali metal reduction of isocyanates is a convenient and rapid method for generating isocyanurate compounds even when a sterically bulky substituent is attached to the NCO moiety.