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Rigid Alicyclic Molecules from Bicyclo[2.2.1]hept‐2‐enes (=8,9,10‐Trinorbornenes) and 1,4‐Dipyridin‐2‐ylphthalazines as Stereoselective Coupling Agents
Author(s) -
Margetić Davor,
Murata Yasujiro,
Komatsu Koichi,
Marinić Željko
Publication year - 2009
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200800205
Subject(s) - chemistry , moiety , phthalazine , alicyclic compound , bicyclic molecule , density functional theory , stereoselectivity , molecule , cycloaddition , reactivity (psychology) , computational chemistry , aromaticity , stereochemistry , medicinal chemistry , organic chemistry , catalysis , medicine , alternative medicine , pathology
For the preparation of rigid polycyclic molecules from 8,9,10‐trinorbornenes (=bicyclo[2.2.1]hept‐2‐enes), 1,4‐dipyridin‐2‐ylphthalazines were used. Cycloaddition reactions with trinorbornenes gave coupled products in a stereoselective manner. In these reactions, the phthalazines delivered a new bicyclo[2.2.2] moiety at the junction of two trinorbornene units, which could bear appropriate functional groups ( Schemes 4 and 5 ). The crystal structure of a key cycloadduct, i.e. , of 18 was also determined ( Fig. 2 ). Relative reactivities for a series of phthalazines ( Fig. 3 ) were estimated by density‐functional‐theory (DFT) calculations at the B3LYP/6‐31G* level ( Table ). The calculations indicated an increase of reactivity when the aromaticity of the phthalazine moiety is decreased. Finally, experimentally observed stereoselectivities of the phthalazine reactions with trinorbornenes were readily predicted by DFT calculations ( Fig. 4 ).