1-(2-Aminopyrimidin-4-yl)ethan-1-one → (R)-1-(2-aminopyrimidin-4-yl)ethanol

To a solution of 1-(2-aminopyrimidin-4-yl)ethanone (Compound 3a) (59.8 g) in N,N-dimethylformide (600 mL) at room temperature was added chloro[(1R,2R)—N-(p-toluenesulfonyl)-1,2-diphenyl-1,2-ethanediamine] (p-cymene)ruthenium (II) (3.35 g). The resulting dark orange solution was then purged with argon and formic acid—triethylamine complex (5:2) (189 g) was added. The reaction was stirred under an atmosphere of argon at room temperature for 1 h then evaporated to dryness under reduced pressure to yield a dark brown residue that was taken up in dichloromethane and the minimal volume of methanol and chromatographed on silica gel eluting with 4-10% methanol in dichloromethane. Fractions containing product were combined and evaporated under reduced pressure to yield the title compound (29.2 g) that was a 2.4%:97.6% ratio of enantiomers by chiral SFC (supercritical fluid chromatography) chromatography.