The compound (VI) can be prepared as a chiral tartrate salt on a two‐kilogram‐scale.

Azetidine derivatives R 0045Asymmetric Synthesis of 2-Mono-and 2,3-trans-Disubstituted Azetidines. -Azetidines (IX) and (XIII) are obtained with excellent diastereomeric and enantiomeric excesses in good overall yields. Key steps are a diastereoselective α-alkylation of aldehyde SAMP-hydrazones with chloride (II), and a nucleophilic 1,2-addition of various organocerium reagents to the hydrazone C=N bond. An epimerization-free reductive removal of the auxiliary and subsequent N-tosylation affords N,O-protected 3-amino-1-alkanols (VI) and (XII). They are converted to the target azetidines by hydrogenolytic cleavage of the benzylic protecting group, followed by ring closure under Mitsunobu conditions. Detosylation is easily achieved by sodium naphthalide. -(ENDERS*, D.; GRIES, J.; KIM, Z.-S.; Eur.

Organic chemistry Z 0200 Asymmetric Syntheses of 4-, 5-and 6-Membered N-Heterocycles Employing the SAMP/RAMP Hydrazone Methodology -[ca. 80 refs.]. -(ENDERS, D.; BOUDOU, M.; GRIES, J.; New Methods Asymmetric Synth. Nitrogen Heterocycl. 2005, 1-31; Inst. Org. Chem., RWTH Aachen, D-52074 Aachen, Germany; Eng.) -Lindner 39-236