Synthesis of 6c. Mes: 2,4,6-trimethylphenyl, TFA: trifluoroacetic acid.
Synthesis of β-LEAP. DIPEA=N,N’-diisopropylethylamine, NMM=4-methylmorpholine, HATU=O-(7-azabenzotriazol-1-yl)-N,N,N’,N’-tetramethyluronium hexafluorophosphate, TEA=triethylamine, TFA=trifluoroacetic acid.