Anthracene-9-methanol, Diels-Alder

The stereospecificity of methanol addition to neopentylsilenes has been investigated by Jones and Bates68. The mild thermal retro-Diels-Alder reaction (at ca 200 °C) of E and Z anthracene [4 + 2] cycloadducts 110 liberates stereospecifically the corresponding silenes 111, which are trapped by methanol. The ratio of the diastereomeric products 396a/396b coincides with the E/Z ratio of the precursors 110 (equation 117). In photochemical reactions of similar silene precursors, alcohols were used also to probe the decomposition mechanism69. 

An attempted synthesis of thiete by thermolysis (300°) of a Diels-Alder adduct with anthracene was unsuccessful, no doubt because of the thermal instability of thiete.Thiete derivative 215 was obtained by other methods, and structure 217 was suggested as an intermediate in the desulfurization of 216. The unusual dithiolactone 218b is formally derived from a cycloaddition of carbon disulfide with acetylene 218a. " A 2-substituted-3,4-diphenyl-2H-thiete is obtained by treatment of the ylide, 8-methyl-1,3-diphenyldibenzo [e, h]-8-thiazulene, with diphenylcyclo-propenethione. 2-Methoxy-3,4-diphenyl-2H-thiete is one of several products obtained on photolysis of diphenylcyclopropenethione in methanol. ... 

The photochemical Diels-Alder reactions of anthracene with fumarodinitrile and 1,4-benzoquinone have been studied in chloroform solution. Not surprisingly, the addition occurs in competition with dimerization of the arene and proceeds by way of electron transfer from anthracene to the dienophiles. The radical ion pair has been detected by transient absorption spectroscopy, and the resulting diradical precursor of adduct formation from the quinone was observed by ESR at 77 K. 2,7-Dibromotropone is reported to undergo (871+471) photoaddition to 9,10-dicyanoanthracene in benzene-methanol (9 1), giving (25) as the primary adduct which is then proposed to react with methanol and water (solvent contaminant) to yield the final product (26). In contrast, 2-bromotropone and the anthracene in CH2CI2 solution afford the substitution products (27) (62%) and (28) (25%). 

Exp. 49, "Diels-Alder Reaction with Anthracene-9-methanol"... 

EXPERIMENT 48 The Diels-Alder Reaction with Anthracene-9-methanol... 

The Diels-Alder reaction with anthracene-9-methanol from Experiment 48. This compound possesses diastereotopic methylene protons, H, and H. ... 

N,N-Diethyl-m-toluamide (OEF), new procedure Diels-Alder Reaction with Anthracene-9-methanol Identification of Unknowns, revised procedure Competing Nucleophiles in S l and Sj. 2 Reactions Investigations Using 2-Pentanol and 3-Pentanol Friedel-Crafts, more substrates added Aqueous-Based Organozinc Reactions... 

B. Diastereotopic Hydrogens The Diels-Alder Adduct of Anthracene-9-methanol and N-Methylmaleimide... 

FIGURE 7.24 The 500 MHz NMR spectrum (CDCI3) of the Diels-Alder product of anthracene-9-methanol and A -methylmaleimide. The insets show expansions of the regions from 3.25 to 3.40 ppm and 4.7 to 5.2 ppm. The eight aromatic ring protons are not shown. Pavia, D. L., G. M. Lampman, G. S. Kiiz, R. 

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