This master's thesis is focus on the decarbonylative C-C bond formation of N-alkylated cyclic α-amino acids followed by the reaction with Grigard reagents. The methodology enables the synthesis of a series of 2-substituted pyrrolidine and piperidine derivatives. The key step involves the formation of iminium intermediates from the acid chloride generated in situ. And Grignard reagents were used as nucleophiles to construct C-C bond. The scope of the Grignard reactions with sp3-, sp2- and sp-carbon nucleophiles was tolerant. The versatility of the method could be used to explore the concise synthesis of bioactive alkaloids. Key word:decarbonylative、C-C bond formation、Grignard reagents