A rapid Diels-Alder approach to halogenated biaryl templates is described. These biaryl templates are available in two steps from the corresponding aromatic aldehydes. The scope of subsequent Suzuki couplings on the biaryl chlorides is explored. Good tolerance for both electron-donating and electron-withdrawing groups in the coupling process can be achieved. Further functionalization of the biaryl templates is described. Hydrogenation of the nitro moiety with concomitant removal of the benzyl ether yields the o-anilino, o-phenolic polyaryls. Selective reduction of the nitro group can be accomplished. Alternatively, the benzyl ether can be selectively removed under Lewis acidic conditions. The utilization of the Diels-Alder adducts for the synthesis of a series of chlorinated carbazoles via the Cadogan cyclization is also demonstrated. Finally, application of this technology to the total synthesis of siamenol, an anti-HIV agent, is reported.

Orthogonally functionalized, programmable biaryl templates have been synthesized utilizing aryl acetylenic stannanes and oxygenated dienes in a cycloaddition/cycloreversion strategy. Sequential functionalization of each of the four ortho positions has been demonstrated. Subsequent resolution of a representative anilino phenol has been accomplished. Additionally, a highly active anhydrous, boroxine-based Suzuki coupling protocol has been developed for conversion of unreactive aryl chlorides.

Polyphenyl derivatives Q 0700Synthesis of Programmable Tetra-ortho-Substituted Biaryl Compounds Using Diels-Alder Cycloadditions/Cycloreversions of Disubstituted Alkynyl Stannanes. -Orthogonally functionalized, programmable biaryl templates are synthesized utilizing aryl acetylenic stannanes and oxygenated dienes in a cycloaddition/ cycloreversion strategy. Sequential functionalization of each of the four ortho positions is demonstrated. Additionally, a highly active anhydrous, boroxine-based Suzuki coupling protocol is developed for conversion of unreactive aryl chlorides. -(PERKINS, J. R.; CARTER*, R. G.; J. Am. Chem. Soc. 130 (2008) 11, 3290-3291; Dep. Chem., Oreg. State Univ., Corvallis, OR 97331, USA; Eng.) -Bartels 31-109

A new method to prepare halogenated biaryls is reported. These compounds are useful synthons which can smoothly be converted into other polyphenyl derivatives such as (VIII) and (IX) as well as to carbazoles like (XIII) and siamenol (XVII). -(NAFFZIGER, M. R.; ASHBURN, B. O.; PERKINS, J. R.; CARTER*, R. G.; J. Org. Chem. 72 (2007) 26, 9857-9865; Dep. Chem., Oreg. State Univ., Corvallis, OR 97331, USA; Eng.) -Jannicke 17-087