Asymmetric synthesis of α‐substituted amino acids and amines by carbon–carbon bond formation in position α to the nitrogen

Abstract

Abstract The asymmetric synthesis of α‐substituted α‐amino acids and propargylamines is described. As chiral auxiliary we used ( S )‐(–)‐1‐dimethoxymethyl‐2‐methoxymethylpyrrolidine (SDMP, 1 ). Treatment of the amino acids or amines with SDMP 1 afforded the corresponding amidines C , which can be metalated and alkylated to yield the products D , which were hydrolyzed to give the desired α‐substituted α‐amino acids 20 and propargylamines 22 . The method allows the enantioselective alkylation of amino acids and propargylamines in satisfactory chemical yields and fair to good enantioselectivity. The chiral auxiliary SDMP 1 is prepared from ( S )‐proline in 4 steps.