ISSN:
1434-193X
Keywords:
Carbanions
;
[2.2]Paracyclophanes
;
Ring annelation
;
Pericyclic reactions
;
Metallocenes
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
[2.2]Paracyclophane-1,9-diene (1) is readily deprotonated at its vinylic positions with BuLi to give the monolithium derivative 2 and - in the presence of TMEDA - even the 1,9-/1,10-dilithium derivatives 1,9-/1,10-6. Reaction of 2 with a variety of electrophiles including benzaldehyde and ethyl formate led to bridge-substituted derivatives 3a-d (71-89% yields) and 4, 5 (95 and 91%, respectively). Electrophilic substitution of 1,9-/1,10-6 with benzaldehyde gave the bis(vinylbenzyl) alcohols 1,9-/1,10-8 in 39% yield. The vinylbenzyl alcohols 5 and 1,9-/1,10-8 underwent cyclization upon treatment with zinc(II) chloride in 1,2-dichloroethane to give the indene-annelated [2.2]paracyclophane 9 (72%) and the bis(indene)-annelated compounds syn-11 and anti-11 (39%, ratio 19:1). Both 9 and syn-11, when treated with FeCl2•(THF)2 after deprotonation with methyllithium in the presence of excess lithium cyclopentadienide gave mixed-ligand ferrocene-type complexes 12 (63%) and syn-/anti-16 (46%). The bis(indeno[2.2]paracyclophane-9-ene) complex 13 was obtained from deprotonated 9 in 61% yield and characterized by an X-ray crystal structure analysis.
Type of Medium:
Electronic Resource
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