Conjugate addition anthrone

Lengthening the side chain produces the antidepressant maprotiline (73), which has a topological relationship to the clinically useful tricyclic antidepressants. The requisite acid is constructed by conjugate addition of the carbanion of anthrone (64) to acrylonitrile, followed by hydrolysis to give 70. Reduction of the carbonyl group with zinc and ammonia gives anthracene 71 by dehydration of the intermediate... 

Other activated methylene-containing nucleophiles that have been successfully used in the conjugate addition to nitrooleflns are a-nitroesters [240], a-cyanoesters [240], a-isocyanoesters [259], 2-hydroxy-1,4-naphthoquinones [260], 3-substituted oxindoles [261], and anthrone [262]. For instance, cupreidine-derived catalysts 151 and 152 (see Fig. 2.15) afford very good yields, diastereo- and enantioselectivities... 

With respect to cupreidine, C9 0-benzoyl esters of this cinchona derivative were demonstrated to be the best catalysts for the nitroaldol reaction of a-ketoesters [55], the conjugate addition of anthrone to nitroalkenes [56], the Henry reaction with fluoromethyl ketones (Scheme 6.25) [57], and an aza-Friedel-Crafts reaction of naphthols with N-sulfonyl imines [58]. 

---