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On the Unusual Dienophilicity of Trimethylsilylphosphaacetylene
Author(s) -
Fiedler Wolfgang,
Löber Oliver,
Bergsträßer Uwe,
Regitz Manfred
Publication year - 1999
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/(sici)1099-0690(199902)1999:2<363::aid-ejoc363>3.0.co;2-2
Subject(s) - chemistry , cyclopentadiene , cycloaddition , intramolecular force , diels–alder reaction , ab initio , ab initio quantum chemistry methods , computational chemistry , diene , stereochemistry , medicinal chemistry , organic chemistry , molecule , catalysis , natural rubber
The diphosphatricyclooctenes 8a , b are obtained from reactions of the phosphaacetylene 2 with the buta‐1,3‐dienes 6a , b through a reaction sequence involving Diels–Alder, ene, and intramolecular [4 + 2] cycloaddition reactions with the intermediates 7 and 9 . An ab initio MO investigation at the MP2/6‐31+G* level of theory has provided reasons why the postulated intermediates cannot be detected. The polycyclic products 8a , b were characterized in the form of the corresponding metal carbonyl complexes 10a , b , and 11 . Reaction of the silylated phosphaalkyne 2 with cyclohexa‐1,4‐diene ( 12 ) furnishes the monophosphatricyclooctene 14 ; this reaction has also been studied by means of ab initio calculations. The result of the reaction of 2 with cyclopentadiene ( 15 ), however, is a complete surprise: the triphosphaspiropolycyclic system 17 is formed, apparently through Diels–Alder, homo‐Diels–Alder, and homo [4 + 1] cycloaddition reactions with the intermediates 16 and 18 .