Lactones arylnaphthalene

Regioselective hydrogenation of anhydrides to lactones. The last step in the synthesis of arylnaphthalene lignans is usually selective hydrogenation of an an-... 

In a series of papers under the rubric of Intramolecular Diels-Alder Reactions during 1963-1976, the cyclization inter alia of phenylpropargyl phenylpropiolate esters, i.e., functionality designed to produce arylnaphthalene lactones essentially in one step, was extensively examined (105). With the aryl rings differently substituted by the common substituents, there is little regioselectivity in the cyclization step. A... 

PT Anastas, R Stevenson. Synthesis of natural lignan arylnaphthalene-lactones, daurinol and retrochinensin. J Nat Prod 54 1687-1691, 1991. 

DDQ in trifluoroacetic acid (TFA) converts (-)-matairesinol dimethyl ether (183a) and (-)-kusunokinin (183b) into the dibenzocyclooctadienes (184a) and (184b) respectively [56]. However, DDQ in dioxane converts (-)-yatein (185) into the arylnaphthalene lactone (186) and the tetrahydronaphthalene lactone (187) [158] (scheme 71). 

Annapoorani K S, Damodaran C, Sekharan P C 1984 Solid-state fluorodensitometric quantitation of arylnaphthalene lignan lactones of Cleistanthus collinus. J Chromatogr 303 296-305... 

Nishii et al. reported metal-mediated benzannulation reaction of diaryl(gm-dichlorocyclopropyl)methanols to synthesize unsymmetrically substituted a-arylnaphthalenes [61]. In particular. The reaction of optically active alcohol 145 in the presence of 1 equiv of HCU at —78 °C afforded chiral biaryl 146 with an excellent level of stereo induction (Scheme 27.48) [62]. It should be noted that chi-raUty exchange from sp central chiraUty to axial chirality takes place in this process. This methodology has been employed successfully for total synthesis of natural lignin lactones, justicidin B, and dehydrodesoxypodophyllotoxin (Scheme 27.49) [63]. 

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