C-glycosides and C-disaccharide precursors through carbonylative Stille coupling reactions
Under CO atmosphere and in the presence of Pd-2(dba)(3) and Ph(3)As a suitably protected 1-stannylglucal derivative could be carbonylated and coupled to 5-bromo-7-oxabicyclo[2.2.1]hept-5-en-2-yl derivatives. The carbonylative Stille coupling was also successful between 1-iodoglucals and tributyl(vinyl)stannane or tributyl(fur-2-yl)stannane. A cross-conjugated dienone was also obtained through coupling of a 1-stannylglucal with a 1-iodoglucal derivative. (C) 1997, Published by Elsevier Science Ltd. All rights reserved.