Isoquinolines Diels-Alder approach

Synthetic Studies on Manzamine A II A novel Diels-Alder Approach to the Pyrrolo[2,3-j]isoquinoline skeleton. Torisawa, Y. Nakagawa, M. Arai, H. Lai,... 

Y. Torisawa, M. Nakagawa, H. Aral, Z. Lai, T. Hino, T. Nakata, T. Oishi, Synthetic studies on manzamine A11 a novel Diels-Alder approach to the pyrrolo[2,3- ]isoquinoline skeleton. Tetrahedron Lett. 31 (1990) 3195-3198. 

Tetrahydroisoquinolines (168) are obtained stereoselectively by cyclization of the lactams (167), induced by polyphosphoric acid (Scheme 68)/ An ingenious, stereoselective approach to the synthesis of reduced isoquinolines (169) is illustrated in Scheme 69. This involves Diels-Alder addition, Wittig alkenylation, and Cope rearrangement reactions. 

Beyond RCM and CM strategies, Craig has reported cleavage using Diels-Alder reactions (Scheme 1.16). ° [4 + 2] Cycloaddition (with concomitant aromatization) of the o-quinodimethane precursor (52) with dimethylacetylene dicarboxylate (DMAD), trichlor-oacetonitrile, and benzoquinone provided dimethyl naphthalene-2,3-dicarboxylate (53), 3-(trichloromethyl)isoquinoline (54), and 2,3-naphthoquinone (55), respectively. The diverse products from a single polymer-supported intermediate, such as the bismuth linkers discussed previously, make Craig s multifunctional linker unit attractive for approaches toward diversity-oriented synthesis. 

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