Abstract A novel and facile synthesis of l -5-hydroxy-2,4-methoxy-3-methylphenylalanine derivatives, which are the key coupling partners for the asymmetric total synthesis of natural bistetrahydroisoquinoline alkaloids, is realized starting from l… Click to show full abstract
Abstract A novel and facile synthesis of l -5-hydroxy-2,4-methoxy-3-methylphenylalanine derivatives, which are the key coupling partners for the asymmetric total synthesis of natural bistetrahydroisoquinoline alkaloids, is realized starting from l -tyrosine with 17% overall yield. The synthesis has been carried out on a multigram scale featuring the following key steps: (a) transformation of phenol to dihydroquinone via salcomine-catalyzed oxidation followed by zinc-acetic acid reduction; (b) single TBS-protection of dihydroquinone; (c) Mitsunobu methylation of the newly generated phenolic hydroxyl group.
               
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