Total synthesis of the salicyldehydroproline-containing antibiotic promysalin

A convergent total synthesis of promysalin, a metabolite of Pseudomonas putida RW10S1 with antibiotic activity, is described. The synthetic approach is based around a salicyldehydroproline core and a dihydroxymyristamide fragment. Crucial steps include a MacMillan asymmetric α-hydroxylation applied for the construction of the myristamide framework, and a lactam reduction by Superhydride® to obtain the dehydroproline fragment. Because of the modular nature of the synthesis, ready access to analogues for biological evaluation is available.