Total Synthesis of Quinoxapeptin A-C: Establishment of Absolute Stereochemistry

The relative and absolute stereochemistry of the naturally occurring potent HIV reverse transcriptase (RT) inhibitors 1 and 2, quinoxapeptin A and B, were established by total synthesis. Their synthetic precursor 3 (dubbed quinoxapeptin C) was found to be a more potent HIV-1 RT inhibitor and to lack the potent cytotoxic activity characteristic of 1 and 2.