Total Synthesis of Darobactin A

The total synthesis of darobactin A, a recently isolated antibiotic that selectively targets Gram-negative bacteria, has been accomplished in a convergent fashion with a longest linear sequence of 16 steps from ᴅ-Garner’s aldehyde and ʟ-serine. Scalable routes towards three non-canonical amino acids were developed to enable the synthesis. The closure of the bismacrocycle was realized through sequential, halogen-selective Larock indole syntheses, where the proper order of cyclizations proved crucial for the formation of the desired atropisomer of the natural product.