Total synthesis of maremycins A, B, C1/C2, D1, and D2

The total synthesis of maremycins A, B, C-1/C-2, D-1, and D-2 is achieved starting from the natural amino acids L-isoleucine and S-methyl-L-cysteine, in which the total synthesis of maremycins B, C-1/C-2, and D-2 is accomplished for the first time. The synthesis features a position-selective intramolecular bromination process for the synthesis of key chiral building block, a Pd-catalyzed indole synthesis for the preparation of (2S,3S)-beta-methyltryptophan and hydroxylation of oxindoles by molecular oxygen. In addition, the protocol for conversion of maremycins A and B to maremycins C and D was improved. (C) 2011 Elsevier Ltd. All rights reserved.