Stereoselective Synthesis of the γ-Lactam Hydrolysate of the Thiopeptide Cyclothiazomycin

[reaction: see text] Bohlmann-Rahtz pyridine synthesis of a chiral nonracemic enamine and thiazolylpropynone gives a terminal-protected pyridine-containing gamma-amino acid in high optical purity in a sequential one-pot multicomponent reaction that proceeds with total control of regiochemistry and with minimal racemization. Further elaboration has established the synthesis of the gamma-lactam acidic hydrolysate of the macrocyclic thiopeptide antibiotic cyclothiazomycin, a selective renin inhibitor, in only four steps and 30% overall yield and has confirmed its structure.