[CH3:1][C:2]1[CH:3]=[C:4]([CH:7]=[CH:8][C:9]=1[CH:10]=C)[C:5]#[N:6].[O:12]=[O+][O-].[BH4-].[Na+].O>CO>[OH:12][CH2:10][C:9]1[CH:8]=[CH:7][C:4]([C:5]#[N:6])=[CH:3][C:2]=1[CH3:1]3-Methyl-4-vinylbenzonitrile (0.40 g; 2.8 mmol; from step (i) above) was dissolved in 50 mL of methanol and cooled to −70° C. Ozone (2 eq.) was bubbled through, and then 0.20 g (5.3 mmol) of sodium borohydride and 5 mL of water were added and the cooling bath was removed. After 4 h the methanol was evaporated and the residue was partitioned between 1M HCl and ether. The aqueous layer was extracted twice with ether and the combined organic phase was washed with water, dried (Na2SO4) and evaporated to yield 0.37 g (90%) of the desired product, which was used in the next step without further purification.
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