A new approach to the synthesis of l-3-hydroxy-4-methoxy-5-methyl-phenylalanine derivatives from l-tyrosine
A practical procedure to regioselectively install a methyl group and a phenolic hydroxyl group onto l-tyrosine was developed. By using this approach, protected l-3-hydroxy-4-methoxy-5-methyl-phenylalanine and l-3-hydroxy-4-methoxy-5-methyl-phenylalanol, which are utilized in efficient syntheses of the relevant tetrahydroisoquinoline alkaloids, were prepared conveniently with high yield.