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Four‐Center Two‐Electron Bonding in a Tetrahedral Topology. Experimental Realization of Three‐Dimensional Homoaromaticity in the 1,3‐Dehydro‐5,7‐adamantanediyl Dication
Author(s) -
Bremer Matthias,
von Ragué Schleyer Paul,
Schötz Karl,
Kausch Michael,
Schindler Michael
Publication year - 1987
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.198707611
Subject(s) - dication , realization (probability) , chemistry , methylene , tetrahedron , crystallography , center (category theory) , stereochemistry , topology (electrical circuits) , computational chemistry , ion , combinatorics , mathematics , medicinal chemistry , organic chemistry , statistics
A nonclassical structure for the dication 3 is supported, in particular, by the 13 C‐NMR data: the signals of the bridgehead C atoms are shifted upfield (δ = 6.6) and not downfield, as would have been expected for a classical dication. The resonances of the methylene C atoms are observed at δ = 35.6 ( 1 H‐NMR: δ = 3.8). Compound 3 is synthesized starting from 1,3,5,7‐tetra‐iodoadamantane, which reacts with HgF 2 to give 1. Compound 1 reacts with n BuLi to give 2 , from which 3 can be generated. The dication 3 is stable up to 0°C.