Premium
Bilden sich aus Pentafulven und Cyclopentadien [6+4]‐Cycloaddukte??
Author(s) -
Niggli Urs,
Neuenschwander Markus
Publication year - 1990
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.19900730817
Subject(s) - chemistry , cyclopentadiene , fulvene , cycloaddition , dimer , homo/lumo , stereochemistry , computational chemistry , photochemistry , crystallography , molecule , organic chemistry , catalysis
Does [6+4] Cycloaddition between Pentafulvene and Cyclopentadiene Take Place? Reaction of a 1:1 mixture of cyclopentadiene (CPD) and pentafulvene ( 1a ) at 20° gives a complex mixture. The low‐molecular‐weight part mainly consists of pure and mixed dimers ( ca. 73 %) besides corresponding trimers ( ca. 20%) and some corresponding oligomers according to GC/MS investigations ( Fig. 1 ). The 3 predominant ‘mixed dimers’ between CPD and 1a have been separated, and structures 4 – 6 ( Scheme 3 ) are assigned according to 400‐ and 600‐MHz 1 H‐NMR investigations. These results show that HOMO(CPD)‐LUMO(fulvene) interactions are important in pentafulvene cycloadditions. Dimer 6 results from [6+4] cycloaddition followed by [1,5]‐H shifts.