Next, the C-H biarylation of the alanine derivative 17 using a Pd(II) catalyst was attempted. Screening of C-H biarylation conditions was conducted based on reported protocols. The optimal conditions, which involved heating alanine derivative 17 and iodinated compound 16 in t-AmOH at 80°C with Pd(OAc)2 (20 mol%) and AgBF4 (1.5 eq.), afforded the desired compound 19 with a 71% isolated yield on a decagram scale (detailed conditions are later discussed in Figure and Table ). This C-H biarylation method is noteworthy for its utility in introducing various biaryl groups to alanine derivative 17, which is valuable in the synthesis of non-natural analogues. Compound 19, obtained via C-H biarylation, was further transformed through several functional group interconversions, yielding Me-ester 20. L-proline derivative 9 was then introduced to compound 20, producing compound 21 to facilitate the study of Larock macrocyclization. Moreover, compound 21 was subjected to coupling with the alkyne fragment 5, resulting in the cyclization precursor 22 for the Larock macrocyclization.