Product 6 then undergoes keto–enol tautomerism to form (S)-scoulerine, which is then methylated by SAM to form (S)-tetrahydrocolumbamine 7.
Product 6 undergoes keto–enol tautomerism to form (S)-scoulerine, which is then converted into (S)-tetrahydrocolumbamine 7 through methylation by SAM.