1.2.3.4- Tetrahydroanthracene

Tetrahydroanthracene is the linear benzologue of Tetralin. This compound behaves identical to Tetralin in the presence of dibenzyl with respect to ring contraction, giving a single methyl signal at 19.6 ppm (Figure 5). Contrary to... 

The complex [Rh(MeOH)2(diphos)]+ (diphos = l,2-bis(diphenylphosphino)eth-ane) has been reported to hydrogenate polynuclear aromatic hydrocarbons under mild conditions (60 °C, 1 bar H2) [17]. A kinetic study of the hydrogenation of 9-CF3CO-anthracene to the corresponding 1,2,3,4-tetrahydroanthracene was consistent with a rapid conversion of the precursor to [Rh( 76-anthracene)(diphos)]+ and a rate-determining step involving the reaction of the latter complex with H2... 

To about 0.54 g. of 9,10-dihydroanthracene in 25 ml. of ethanol, 8 g. of Raney nickel catalyst was added. After refluxing for 2J hours in an atmosphere of nitrogen, the mixture was filtered and the filtrate was concentrated. On cooling, about 0.33 g. of 1,2,3,4-tetrahydroanthracene was obtained. The mother liquor, when treated with 0.3 g. of s-trinitro-benzene, yielded about 0.25 g. of the 1,2,3,4-tetrahydroanthracene-tri-nitrobenzene complex. The total yield was 81% of the theoretical. When about 0.34 g. of anthracene in 50 ml. of ethanol was treated with 10 g. of Raney nickel, a 71 % yield of the same product was obtained. 

With nickel(II) 2-ethylhexanoate and triethylaluminum, tetralin (59) is obtained by hydrogenation of naphthalene (55). Polycyclic aromatics, such as anthracene (57 equation 8), 9-methylanthracene and 9-trifluoroacetylanthracene, are partially hydrogenated to 1,2,3,4-tetrahydroanthracene derivatives by use of [Rh(DPPE)(arene)]+ in methanol and by ruthenium hydride complexes having triphenylphosphine ligands... 

Problem 30.22 Account for the following observations (a) Upon treatment with hydrogen and nickel, 9,10-dihydroanthracene yields 1,2,3,4-tetrahydroanthracene. (b) In contrast to bromination, sulfonation of anthracene yields the 1-sulfonic acid. 

A very different set of interesting d niobium and tantalum hydride catalysts containing bulky aryloxide ligands recently reported by Rothwell [52-54] appear very promising. For instance, naphthalene and anthracene are reduced at 80 C and 3-100 atm Hj by [Ta(OC H3(C H,)2-2,6 2(H)j(PMc,Ph)] to produce mainly tetralin or 1,2,3,4-tetrahydroanthracene, respectively. 

A particularly active catalyst for the hydrogenation of polycylic arenes has been generated from the anionic hydridoruthenium precatalyst in Figure 15.18, discovered by Grey and Fez. This system catalyzes the hydrogenation of antliracene to 1,2,3,4-tetrahydroanthracene under relatively mild conditions with a turnover frequency of > 50 h" and a turnover number of > 100 (Equation 15.96). Both anthracene and naphthalene are partially hydrogenated in the presence of tlais catalyst, but monocyclic arenes do not react. 

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