Bis(1,5-cyclooctadiene)rhodium(I) tetrafluoroborate

1. Convenient catalyst precursor, for example, with (R,R)QuinoxP* for asymmetric alkylations and hydrogenations.
2. Catalyst precursor with chiral biaryl bisphosphine ligands for [2+2+2] enantioenriched cycloadditions. 

dark red

Bis(1,5-cyclooctadiene)rhodium(I) tetrafluoroborate is useful for hydrogenation, isomerization reactions and is also employed as a precursor for asymmetric hydrogenations. Furthermore, it is used in the synthesis of cationic COD-Rhodium complexes with phosphine ligands. In addition, it shows an important application for enantioselective hydrogenation and hydrosilylation.

core: rhodium
reagent type: catalyst

10 grams of rhodium trichloride trihydrate dissolved in 100 ml of anhydrous ethanol and 20 ml of water, measure 37.4 ml of 1,5-cyclooctadiene in a constant pressure funnel, nitrogen displacement protection, the beginning of the dropwise addition of 1,5-cyclooctadiene, dropwise addition is completed, the temperature rise to 82 and keep warm stirring for 18 hours. The reaction solution was concentrated by evaporation, cooled and filtered to obtain 1,5-cyclooctadiene rhodium(II) chloride dimer. Then dissolve all of the above solid in 240 ml of dichloromethane and 17.7 ml of 1,5-cyclooctadiene, protected by nitrogen, slowly dropwise add 60 ml of acetone solution containing 7.5 g of silver tetrafluoroborate at 20 , dropwise raise the temperature to 35 and react for 24 hours, filtration, spinning and concentrating, filtration, rinsed with methyl tert-butyl ether, vacuum drying at room temperature, to obtain bis(1,5-cyclooctadiene)tetrafluorine Rhodium(I) borate 13.8 g, the measured metal Rh content 24.92%, the theoretical Rh content 25.30%.