Syntheses of α‐Amino Acids by Using CO2 as a C1 Source

The incorporation of CO2 into organic compounds is currently one of the most active research topics in organic chemistry, because CO2 is an abundant, inexpensive, nontoxic, and renewable C1 source. However, CO2 is also a thermodynamically stable and kinetically inert gaseous compound, and as such, special strategies are required to activate CO2 and incorporate it into organic compounds. In particular, because the carbon atom adjacent to the nitrogen atom of amine derivatives is positively charged, umpolung carboxylation, which is a difficult chemical process, should be considered for the production of α‐amino acids by using CO2. In this Minireview, we summarize recent synthetic methods for α‐amino acids that use CO2 as a carboxylic acid unit. C1, do one, teach one: CO2 is an ideal resource for the synthesis of value‐added organic compounds. This Minireview summarizes recent synthetic methods for α‐amino acids by using CO2, especially through carbanion‐like intermediates.