Anthracenes 9-substituted, microwave

The scope of the microwave technique in the preparation of fullerene derivatives was determined in the well known Diels-Alder reaction of C6o with anthracene (1) [71], which has been reported to occur under thermal conditions (13% [71a], reflux, toluene, three days 25% [71b], reflux, benzene, 12 h) (Scheme 9.22). In addition to 76, multiply-substituted adducts that undergo cycloreversion to the starting materials were formed. 

Microwave-assisted Diels-Alder reactions of 9-substituted anthracenes with 2-acetamidoacrylate in DMF generate conformationally constrained bicyclic bisaryl a-amino acid derivatives with high regioselectivity.138 The Sc(OTf)3-catalysed Diels-Alder reaction of anthracenes with methyl vinyl ketone does not proceed via an electron-transfer process from anthracenes to the MVK-Sc(OTf)3 complex.139 (-)-(/ )-9-(l,2-Dimethoxyethyl)anthracene has been used as a chiral template in the Diels-Alder/retro-Diels-Alder sequence for the synthesis of a,j3-unsaturated lactams.140... 

Numerous unsuccessful attempts to synthesize cyclopropanethione have been reported. Thermal or photochemical generation of the C3H4S species from different sources always leads to allene episulfide. Some representative experiments include (a) in vacuo pyrolysis of the sodium salt of 2,2,4,4-tetramethylthietanone tosylhydrazone (4) into the stable tetramethylallene episulfide (S), (b) pyrolytic extrusion of nitrogen from perfluorinated thiadiazoline 6, (c) in vacuo pyrolysis of spiro compound 8 into methylenethiirane (3), (d) the flash vacuum pyrolysis-microwave spectroscopic approach applied to spiro compounds 9 and 10, (e) pyrolysis of anthracene adduct 11 and tosylhydrazide salt 12, (f) thermolytic nitrogen extrusion from pyrazoline-4-thione 13, thermolysis of tetramethylallene episulfide (5) or pyrazoline 13 in dig-lyme solution, and photolytic nitrogen extrusion from pyrazoline 13, ° (g) thionation of methylenecyclopropanone 15, and (h) reaction of donor-acceptor substituted allenes 18 with elemental sulfur. ... 

Hofmann used a triptycene type backbone for preparing diphosphite 145, in overall 40% yield from three steps, starting from a conveniently substituted anthracene. Reaction of the substituted anthracene with dimethyl fumarate under microwave irradiation considerably reduced reaction time to prepare the triptycene derivative. After deprotection, the corresponding diol was then treated with chlorophosphite to give 145. The ligand was used in theoretical studies on rhodium(i)-catalysed hydroformylation of butadiene. The same authors also prepared iridium complex 146, from the already known diphosphite, which was used for the same purpose. 

Chan et al. (2009) observed nucleophilic substitution of halogen group from polycyclic aromatic halides with various N-, S-, and Se-nucleophiles to afford substituted phenanthrenes, anthracenes, acenaphthenes, and fluorenes under microwave heating to have good to excellent yields in a short reaction time. 

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