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Preparation of [5 + 6]‐, [6 + 6]‐, and [6 + 7]‐Bicyclic Guanidines from C,C '‐Bis(iminophosphoranes)
Author(s) -
Molina Pedro,
Obòn Rosario,
Conesa Carlota,
Arques Antonio,
De Velasco M. Los Desamparados,
LlamasSaiz Antonio L.,
FocesFoces Concepciòn
Publication year - 1994
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19941270916
Subject(s) - bicyclic molecule , chemistry , annulation , molecule , dimer , hydrogen bond , guanidine , crystal structure , stereochemistry , crystallography , catalysis , organic chemistry
A one‐pot synthesis of [5 + 6]‐, [6 + 6]‐, and [6 + 7]‐rigid bicyclic guanidines ( 6 , 8 , 19 , 21 , 23 ) based on a bis(iminophosphorane)‐mediated annulation strategy is reported. The crystal and molecular structure of the parent [5 + 6]‐bicyclic guanidine 8 has been established by X‐ray diffraction. The crystallographically independent molecule forms dimers through a centre of symmetry by N–H–N hydrogen bonds. The molecule, and therefore the dimer, is statistically disordered in a 65/35 ratio. A statistical study of N–H–N hydrogen bonds of this kind of dimers has been carried out by using the Cambridge Structural Database.