Asymmetric Synthesis of 2-Substituted Azetidin-3-ones via Metalated SAMP/RAMP Hydrazones

Highly Selective Synthesis of α-Aminoamide Utilizing an Umpolung Reaction and Characteristics of α-Hydrazonoester

An umpolung reaction with α-hydrazonoesters was investigated, and it was found that α-N,N-dialkylaminoamides could be directly synthesized in yields up to 92% via a concomitant rearrangement of dialkylamino groups. As an application, a short synthesis of an inhibitor of glycine type-1-transporter was accomplished via subsequent functional group transformations in 28% overall yield.

Synthesis of 3,3-Diarylazetidines by Calcium(II)-Catalyzed Friedel-Crafts Reaction of Azetidinols with Unexpected Cbz Enhanced Reactivity

Azetidines are valuable motifs that readily access under explored chemical space for drug discovery. 3,3-Diarylazetidines are prepared in high yield from N-Cbz azetidinols in a calcium(II)-catalyzed Friedel-Crafts alkylation of (hetero)aromatics and phenols, including complex phenols such as β-estradiol. Electron poor phenols undergo O-alkylation. The product azetidines can be derivatized to drug-like compounds through the azetidine nitrogen and the aromatic groups. The N-Cbz group is crucial to reactivity by providing stabilization of an intermediate carbocation on the four-membered ring.