Synthesis of chiral lithium carbamates from (S)-2-(N,N-dialkyl-aminomethyl)pyrrolidines and (S)-methoxymethylpyrrolidine

A convenient synthesis of chiral lithium N-alkyl carbamates 1a–4a from chiral pyrrolidines 1–4, LiH and CO2 is described. The yields are good to excellent. A combined experimental (1H, 6Li-HOESY, cryoscopy) and theoretical study (B3LYP/6-311++G(d,p)) succeeded in assigning the predominant solution state structure of 1a.