In:
Chemistry – A European Journal, Wiley, Vol. 9, No. 11 ( 2003-06-06), p. 2469-2483
Abstract:
In the presence of 2.5 mol % of [Pd 2 (dba) 3 ] (dba=dibenzylideneacetone) and 5 mol % of PPh 3 , nearly equimolar amounts of dimethyl nona‐2,7‐diyne‐1,9‐dioate derivatives (diyne diesters) and dialkyl acetylenedicarboxylates were allowed to react in toluene at 110 °C to afford [2+2+2] cycloadducts in moderate‐to‐good yields. Similarly, dimethyl trideca‐2,7,12‐triyne‐1,13‐dioate derivatives (triyne diesters) were catalytically transformed into phthalic acid ester analogues in excellent yields. To gain insight into the mechanism of these intramolecular alkyne cyclotrimerizations, stoichiometric reactions of [Pd 2 (dba) 3 ] with a diyne diester and a triyne diester bearing ether tethers were conducted in acetone at room temperature to furnish an oligomeric bicyclopalladacyclopentadiene and a Pd 0 triyne complex, respectively. The structures of these novel complexes were unequivocally determined by Xray structure analysis. The isolated triyne complex was heated at 50 °C or treated with PPh 3 in acetone at room temperature to afford the arene product. Furthermore, the same complex catalyzed the triyne cyclization with or without PPh 3 .
Type of Medium:
Online Resource
ISSN:
0947-6539
,
1521-3765
DOI:
10.1002/chem.200204540
Language:
English
Publisher:
Wiley
Publication Date:
2003
detail.hit.zdb_id:
1478547-X
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