The alkali-metal salts (potassium and sodium) of a large number of aryl- and heteroarylsilanols undergo efficient cross-coupling with a wide range of aromatic bromides and chlorides under mild conditions to form polysubstituted biaryls. The critical feature for the success of these coupling reactions and their considerable scope is the use of bis(tri-tert-butylphosphine)palladium. Under the optimized conditions, electron-rich, electron-poor, and sterically hindered arylsilanolates afford cross-coupling products in good yields. Many functional groups are compatible with the coupling conditions such as esters, ketones, acetals, ethers, silyl ethers, and dimethylamino groups. Two particularly challenging substrates, (2-benzofuranyl)dimethylsilanolate and (2,6-dichlorophenyl)dimethylsilanolate prepared as their sodium salts showed excellent activity in the coupling reactions, in the former case also with aromatic chlorides. General methods for the efficient synthesis of a wide range of aromatic silanols are also described.
The alkali-metal salts (n class="Chemical">potassium and sodium) of a large number of aryl- and heteroarylsilanols undergo efficient cross-coupling with a wide range of aromatic bromides and chlorides under mild conditions to form polysubstituted biaryls. The critical feature for the success of these coupling reactions and their considerable scope is the use of bis(tri-tert-butylphosphine)palladium. Under the optimized conditions, electron-rich, electron-poor, and sterically hindered arylsilanolates afford cross-coupling products in good yields. Many functional groups are compatible with the coupling conditions such as esters, ketones, acetals, ethers, silyl ethers, and dimethylamino groups. Two particularly challenging substrates, (2-benzofuranyl)dimethylsilanolate and (2,6-dichlorophenyl)dimethylsilanolate prepared as their sodium salts showed excellent activity in the coupling reactions, in the former case also with aromatic chlorides. General methods for the efficient synthesis of a wide range of aromatic silanols are also described.
Authors: Moorthy S S Palanki; Hideo Akiyama; Peter Campochiaro; Jianguo Cao; Chun P Chow; Luis Dellamary; John Doukas; Richard Fine; Colleen Gritzen; John D Hood; Steven Hu; Shu Kachi; Xinshan Kang; Boris Klebansky; Ahmed Kousba; Dan Lohse; Chi Ching Mak; Michael Martin; Andrew McPherson; Ved P Pathak; Joel Renick; Richard Soll; Naoyasu Umeda; Shiyin Yee; Katsutoshi Yokoi; Binqi Zeng; Hong Zhu; Glenn Noronha Journal: J Med Chem Date: 2008-02-27 Impact factor: 7.446