HCID 86651762, compound → HCID 23722193, compound

Participants

Reaction Steps

DPPOBS-Na (7.0 g; 18.4 mmoL), prepared as above, is dissolved in dry methanol (70 mL) and placed into a Parr reactor (150 mL) containing 7 g of catalyst comprising Ru (5 wt percent) on carbon. Hydrogenation is carried out at 1,000 psi (6,895 kPa) hydrogen and at 100° C. The reaction is monitored by 31P and 1H NMR. After 2 weeks, resonances for the aromatic protons in the 1H NMR spectrum disappear, and new resonances appear in the 31P NMR spectrum. The mixture is filtered; a black solid on the filter is washed with methanol. The solvent is evaporated, and the residue is dried in vacuum to give a white solid identified as sodium 3-(dicyclohexylphosphinyl)cyclohexane-1-sulfonate (DCHPOCHS-Na). Yield 4.0 g (55%). 31P{1H} NMR (CD3OD, ppm): 5.68 (major, ca. 87%) and 57.99 (minor, ca. 13%). (3) Step 3 of Example 1 is repeated using the intermediate product from step (2) of this example. Subsequently, steps 4 to 6 of Example 1 are also reproduced to yield Ligand 1 of this invention, namely, the sodium salt of 3-(dicyclohexylphosphino)cyclohexane-1-sulfonic acid.

Provenance & Evidence