Synthesis of β-alkynyl α-amino acids via palladium-catalyzed alkynylation of unactivated C（sp3）-H bonds

β-Di-substituted α-amino acids （AAs） contain adjacent carbon stereogenic centers and pose considerable synthetic challenge. Complementary to the conventional synthesis strategies based on the transformation of existing functional groups, we envi- sioned these molecules could be quickly accessed via selective functionalization of sp3 hybridized C-H bonds on the side chains of common α-AA precursors. We report a readily applicable method to prepare β-alkynyl α-amino acids via Pd-cata- lyzed diastereoselective C（sp3）-H alkynylation of common α-amino acids precursors with acetylene bromide.