77647-98-4

Upstream product

• 104-63-2 N-Benzylethanolamine 
• 107-59-5 tert-Butyl chloroacetate 
• 1269460-91-4 C₁₅H₂₂ClNO₂ 
• 168263-75-0 tert-butyl 2-(benzyl-(2-hydroxyethyl)amino)-acetate 
• 77629-96-0 2,4-dibromobutyric acid tert-butyl ester 
• 100-46-9 benzylamine 

Downstream Products

• 70339-93-4 N-Benzyl-Δ¹-azetinium Perchlorate 
• 1269461-40-6 C₁₂H₁₄N₄O₂ 
• 1269461-42-8 C₁₃H₁₄N₂O₂ 
• 31247-34-4 (1-benzyl-azetidin-2-yl)-methanol 
• 1353161-08-6 tert-butyl N-benzyl-2-(2-methoxycarbonylethyl)azetidine-2-carboxylate 
• 4458-64-4 N-benzyl-2-azetidinone 

Relevant academic research and scientific papers

Structural and mechanistic studies of the base-induced Sommelet-Hauser rearrangement of: N -α-branched benzylic azetidine-2-carboxylic acid-derived ammonium salts

The base-induced Sommelet-Hauser rearrangement of N-α-branched benzylic azetidine-2-carboxylic acid ester-derived ammonium salts to obtain α-arylazetidine-2-carboxylic acid esters was investigated. The substrates, two diastereomeric salts (1S,2S,1′S)- and (1R,2R,1′S)-2, showed different reactivities. The rearrangement of (1S,2S,1′S)-2a proceeded with a perfect N-to-C chirality transfer to provide (R)-3a in 74% yield with 99% ee. However, the rearrangement of (1R,2R,1′S)-2a under the same conditions afforded (S)-3a in only 15% yield with a lower 66% ee, along with the competitive [1,2] Stevens rearrangement product 4a. Structural and mechanistic studies of this rearrangement were carried out to clarify the exact reason. Our results define the scope and limitations of the Sommelet-Hauser rearrangement and provide unique synthetic access to α-aryl amino acid derivatives.

Ring-Strain Effects in Base-Induced Sommelet–Hauser Rearrangement: Application to Successive Stereocontrolled Transformations

The base-induced Sommelet–Hauser (S–H) rearrangement of azetidine-2-carboxylic acid ester-derived ammonium salts into 2-aryl-substituted derivatives was demonstrated. The ring-strain of four-membered N-heterocycles enables efficient generation of the desired ylide intermediate and enhances the rate of the S–H rearrangement. The asymmetric version of the rearrangement was characterized by excellent levels of successive chirality transmissions. The regio- and stereo-controlled nucleophilic ring opening of the rearrangement products produced quaternary α-aryl amino acid esters with excellent enantiopurities.

Synthesis of spirocyclopropyl γ-lactams by tandem intramolecular azetidine ring-opening/closing cascade reaction: Synthetic and mechanistic aspects

The scope and limitations of a novel intramolecular azetidine ring-opening/closing cascade reaction affording spirocyclopropyl γ-lactams from azetidines in high regio- and stereoselectivity is reported. The key step of the process is a SN2-type ring-opening of TMSOTf-activated azetidine rings by silyl ketene acetals generated by treatment with TMSOTf and TEA. This study is a very rare example of nucleophilic ring-opening of azetidines that does not require formation of quaternary azetidinium salts by N-alkylation or the use of N-electron-withdrawing groups. Application of this process to 2-azetidinone system led to a complete change in reactivity and provide 6-aza-bicyclo[3.2.0]heptane derivatives via an unprecedented Mukaiyama aldol-like reaction involving an ester acceptor and a silyl imidate.

Ring expansion of 2-(1-Hydroxyalkyl)azetidines to 4-(2-Chloroethyl) oxazolidinones

2-(1-Hydroxyalkyl)azetidines react with bis(trichloromethyl) carbonate (BTC) after basic treatment to afford 4-(2-chloroethyl)oxazolidinones. The scope of this rearrangement was examined in detail and its efficiency was shown to depend on the class of the