Rhodium-diphosphite catalysed hydroformylation of allylbenzene and propenylbenzene derivatives

The asymmetric hydroformylation of allylbenzenes and propenylbenzenes is an important tool for obtaining high value intermediates for the pharmaceutical and perfume industry. We have studied these reactions with rhodium-chiral diphosphite systems. The diphosphite ligands 6 and 7 with carbohydrate backbone have high regioselectivities in trans-anethole hydroformylation and moderate ones in estragole hydroformylation. Only low enantioselectivities have been observed in the trans-anethole hydroformylation with the diphosphite 6 based system.