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Versuche zur Synthese von [2.2]‐ und [2.3]Cyclopentadienophanen
Author(s) -
Fischer Marcel,
Bönzli Peter,
Stofer Brigitte,
Neuenschwander Markus
Publication year - 1999
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/(sici)1522-2675(19990908)82:9<1509::aid-hlca1509>3.0.co;2-e
Subject(s) - chemistry , stereochemistry , tautomer , condensation , molecule , medicinal chemistry , organic chemistry , physics , thermodynamics
Synthetic Attempts towards [2.2]‐ and [2.3]Cyclopentadienophanes . The first [2.2]Cyclopentadienophane (=2,2,3,3,8,8,9,9‐octamethyltricyclo[8.2.1.1 4,7 ]tetradecatetraene; 1b ) has been synthesized ( Scheme 5 ) by reductive coupling of 6,6‐dimethylfulvene 3 → 5 (50%) followed by base‐induced twofold condensation of 1,2‐di(cyclopentadienyl)‐1,2‐dimethylbutane 5 with acetone to give difulvene 15 (95%). Reductive coupling of 15 gives a complex mixture of tautomers of 16 , 17 , and 1b , which contains ca . 50% of the target molecule 1b . Other synthetic attempts towards [2.2]cyclopentadienophanes 1a and 1b and [2.3]cyclopentadienophane 18 are discussed.