Selective Palladium-Catalyzed Cocyclotrimerization of Arynes
with Dimethyl Acetylenedicarboxylate: A Versatile Method for the
Synthesis of Polycyclic Aromatic Hydrocarbons<sup>†</sup>
Diego Peña
Dolores Pérez
Enrique Guitián
Luis Castedo
10.1021/jo000535a.s001
https://acs.figshare.com/articles/journal_contribution/Selective_Palladium-Catalyzed_Cocyclotrimerization_of_Arynes_with_Dimethyl_Acetylenedicarboxylate_A_Versatile_Method_for_the_Synthesis_of_Polycyclic_Aromatic_Hydrocarbons_sup_sup_/3685710
Benzyne (<b>1a</b>) and the substituted derivatives 4,5-difluorobenzyne (<b>1b</b>) and 3-methoxybenzyne (<b>2</b>)
undergo chemoselective palladium-catalyzed [2 + 2 + 2]-cocyclotrimerization with dimethyl
acetylenedicarboxylate (DMAD) to afford the corresponding phenanthrenes and/or naphthalenes.
The major products are phenanthrenes if Pd(PPh<sub>3</sub>)<sub>4</sub> is used as the catalyst, naphthalenes if
Pd<sub>2</sub>(dba)<sub>3</sub> is used. When the method is applied to polycyclic arynes <b>3</b>−<b>6</b>, which are generated from
the corresponding <i>o</i>-trimethylsilylaryl triflates, the same reactivity pattern is observed: the reaction
can be selectively directed either toward the cocyclization of one molecule of aryne and two molecules
of alkyne or to the reaction of two molecules of aryne with one molecule of alkyne, by appropriate
choice of the palladium catalyst. The synthesis of polycyclic aromatic compounds <b>33</b>−<b>39 </b>using this
methodology is reported.
2000-09-16 00:00:00
Pd 2
aryne
reactivity pattern
naphthalene
dimethyl acetylenedicarboxylate
phenanthrene
alkyne
Versatile Method
DMAD
molecule
polycyclic
trimethylsilylaryl triflates
palladium catalyst
1 b