Applying asymmetric dihydroxylation to the synthesis of difluorinated carbohydratre analogues: a 1,1-difluoro-1-deoxy-D-xylulose

Readily available difluoroenol iodides and stannanes undergo palladium-catalysed coupling reactions with alkenylstannanes and iodides, respectively, to afford a trial set of difluorinated 1,3- and 1,4-dienes, which were then exposed to AD conditions. A number of issues were raised including generally low reactivity of simple 1,3-butadienes, and useful reactivity of certain 1,4- and substituted 1,3-pentadienes. Though the basic conditions used for the AD resulted in the decomposition of certain diol products, enol acetal chemistry allowed the asymmetric synthesis of a difluorinated analogue of a deoxyxylulose. (C) 2004 Elsevier Ltd. All rights reserved.