215-26-9Relevant academic research and scientific papers
Cycloadducts of Arynes with 1,3-Bis(trimethylsilyl)naphthofuran: Formation of Novel Polycyclic Aromatic Derivatives and Related Reactions
Pollart, Daniel J.,Rickborn, Bruce
, p. 3155 - 3161 (1986)
A recently developed procedure for the preparation of trimethylsilylated isobenzofurans and the use of these materials in cycloaddition reactions has been extended to an isonaphthofuran analogue.The 1,3-bis(trimethylsilyl)naphthofuran (7) has been isolated; its reaction with maleic anhydride in room temperature is rapid and readily reversible as shown by endo to exo cycloadduct interconversion.The failure of 7 to give cycloadduct with 2-butenolide indicates that it is less reactive than the parent naphthofuran.In situ generation and cycloaddition reactions with various arynes (benzyne, 4-methylbenzyne, 3,4-pyridyne, 9,10-phenanthrolyne, 1,2-naphthalyne, 2,3-naphthalyne) are described.The three unsymmetrical arynes all give mixtures of cycloadducts indicative of negligible regioselectivity in Diels-Alder reactions with 7; thus, in spite of possible steric hindrance the reaction with 1,2-naphthalyne gives a 1:1 mixture of dibenz- and dibenzanthracene derivatives.In contrast, the reaction of 1-ethoxy-3-(trimethylsilyl)naphthoanthracene derivative.Various reactions of the cycloadducts are described.
A Rapid, Convergent, and Regioselective Synthesis of Anthracenes
Fitzgerald, John J.,Drysdale, Neville E.,Olofson, R. A.
, p. 7122 - 7126 (1992)
Anthracenes are obtained in moderate to good yield by the simultaneous treatment of benzocyclobutenols and halobenzenes with LTMP in tetrahydropyran.In the key step of this one-pot process, o-toluoyl anion intermediates from the known ring-opening of benzocyclobutenoxides add to halobenzene derived arynes.Methoxy-substituted benzocyclobutenols which are readily made regiospecifically by known methods also react regiospecifically with the single benzyne generated from either a 2- or 3-haloanisole.For example, the only trimethoxyanthracene isolated (48percent yield) from the reaction of 6-methoxybenzocyclobutenol (8) with 5-chloro-1,3-dimethoxybenzene is the 1,3,8-isomer 20.When 1,2-dihydrocyclobutaphenanthren-1-ol (14) and/or halonaphthalenes are the reactants, benzannulated anthracenes are formed; e.g., tribenzanthracene in 68percent yield from 14 and bromonaphthalene.In another extension, pentaphene (31) was made in one pot from o-dichlorobenzene.
