Carbon dioxide (CO₂) is an abundant, inexpensive, relatively nontoxic, and renewable C1 source for organic synthesis, fixations of which have been intensively studied over the past decade. For the purpose of preparing valuable commodity chemicals from easily accessible starting materials through CO₂ incorporation, we have made many efforts toward the development of α-amino acid synthesis from CO₂ and imines. By changing the latent polarity of imino carbon by treatment of a stannyl or a silyl anion derived from CsF and bismetal reagents (Me₃Si-SnBu₃ or PhMe₂Si-Bpin) with imine, we successfully developed a one-pot synthesis of N-Boc-α-amino acids from gaseous CO₂ and N-Boc-α-amido sulfones (stable N-Boc-imine precursors). In addition, we have developed a one-pot α-amino acid synthesis from three basic components, CO₂, an aldehyde, and a sulfonamide, promoted by Bu₃Sn-SnBu₃ and CsF. Intermediates of these α-amino acid syntheses are imines and α-amino stannanes or α-amino silanes.