Furanoside diphosphines derived from D-(+)-xylose and D-(+)-glucose as ligands in rhodium-catalysed asymmetric hydroformylation reactions

Chirality transfer by furanoside diphosphines 1-3 was investigated in the R h-catalysed asymmetric hydroformylation of prochiral olefins. In general, t hey induced high regioselectivities with branched aldehydes and moderate en antioselectivities of up to 58%. Improved activities were seen when a methy l substituent was introduced at C-(5) of the sugar residue. Systematic vari ation of the configuration at C-(5) suggests that there is a cooperative ef fect between stereocentres, which results in a matched combination for liga nd 3 with (R)-configuration at the C-(5) stereogenic centre. Introduction o f a methyl substituent at C-(5) induces a strong coordination preference. T he solution structures of the species formed under hydroformylation conditi ons were also investigated. (C) 2001 Elsevier Science Ltd. All rights reser ved.