Asymmetric introduction of nucleophiles to the 2-position of pyrrolidine ring through N-acylpyrrolidinium ion

Asymmetric carbon-carbon bond-forming reaction at the 2-position of a pyrrolidine ring was achieved. The reaction involved a chiral Ti(IV) catalyzed coupling between 1 -methoxycarboyl-2-methoxypyrrolidine and silyl enol ethers to afford 2-substituted pyrrolidines with up to 53 % ee.