On the Unusual Dienophilicity of Trimethylsilylphosphaacetylene

✍ Scribed by Wolfgang Fiedler; Oliver Löber; Uwe Bergsträßer; Manfred Regitz

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 224 KB
• Volume: 1999
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/(sici)1099-0690(199902)1999:2<363::aid-ejoc363>3.0.co;2-2

✦ Synopsis

The diphosphatricyclooctenes 8a, b are obtained from Reaction of the silylated phosphaalkyne 2 with cyclohexa-1,4-diene (12) furnishes the monophosphatricyclooctene 14; reactions of the phosphaacetylene 2 with the buta-1,3-dienes 6a, b through a reaction sequence involving Diels-Alder, this reaction has also been studied by means of ab initio calculations. The result of the reaction of 2 with ene, and intramolecular [4 + 2] cycloaddition reactions with the intermediates 7 and 9. An ab initio MO investigation at cyclopentadiene (15), however, is a complete surprise: the triphosphaspiropolycyclic system 17 is formed, apparently the MP2/6-31+G* level of theory has provided reasons why the postulated intermediates cannot be detected. The through Diels-Alder, homo-Diels-Alder, and homo [4 + 1] cycloaddition reactions with the intermediates 16 and 18. polycyclic products 8a, b were characterized in the form of the corresponding metal carbonyl complexes 10a, b, and 11.