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The Azo(Azoxy) Functionality as a π 2 Component in Photo [2+2] cycloadditions ‘ syn ’‐ and ‘ anti ’‐3,4‐diazatricyclo[4.2.2.2 2,5 ]dodeca‐3,7‐diene, syntheses, photolyses, X‐ray‐structure analysis, and PE spectra
Author(s) -
Marterer Wolfgang,
Prinzbach Horst,
Rihs Grety,
Wirz Jakob,
Lecoultre Jaques,
Heilbronner Edgar
Publication year - 1988
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.19880710813
Subject(s) - chemistry , pericyclic reaction , azoxy , steric effects , cycloaddition , stereochemistry , photochemistry , computational chemistry , medicinal chemistry , organic chemistry , catalysis
The propensity of the NN bond to undergo photo [2 + 2] cycloadditions has been further explored. In the specifically designed 1,5‐azo/enes 1–3 , no [2 + 2] cycloaddition has been observed upon either direct or sensitized excitation with light of various wave lengths at temperatures down to 77 K, in line with expectations based on X‐ray ( 1 : d = 2.71 Å, ω = 129°) and PE measurements ( 1 : I 1 = 8.0 0 , I 2 = 9.0 5 eV; 2 ; I 1 = 8.0 0 , I 2 = 9.2 5 eV). The steric/stereoelectronic demands for the participation of the NN bond in pericyclic reactions are clearly more stringent than those for the CC bond.