2001 fused pyrimidine derivatives

fused pyrimidine derivativesR 0515

10 - 149The Synthesis of C2-Symmetric and Axially Chiral Compounds forRecognition and Catalysis. — With the aim to design potential axiallychiral catalysts for reactions of α,β-unsaturated substrates, several attempts aremade to prepare biaryls using Stille, Suzuki, and Ullmann coupling methods askey steps. Compound (III) and (VIII) are successfully synthesized under Suzukiconditions, albeit in poor yields. An alternative strategy, avoiding the couplingof two sterically demanding tricycles, is developed for the synthesis of biaryl(VI) via homocoupling of bromide (IV) under Ullmann conditions leading tothe desired intermediate biaryl (V). Further elaboration of the latter productinvolving the reduction of the nitro group, saponification of the methyl ester,and two consecutive condensation reactions would give access to the targetcompound (VI). — (CLEWS, JOHN; CURTIS, ANTHONY D. M.; MALKIN,HUGH; Tetrahedron 56 (2000) 44, 8735-8746; Sch. Chem. Phys., Keele Univ.,Keele, Staffordshire ST5 5BG, UK; EN)

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