Ring‐Opening Reactions of 3‐Aryl‐1‐benzylaziridine‐2‐carboxylates and Application to the Asymmetric Synthesis of an Amphetamine‐Type Compound
2007; Wiley; Volume: 90; Issue: 1 Linguagem: Inglês
10.1002/hlca.200790006
ISSN1522-2675
AutoresTomoyuki Manaka, Shin‐ichiro Nagayama, Wannaporn Desadee, Naoki Yajima, Takuya Kumamoto, Toshiko Watanabe, Tsutomu Ishikawa, Masatoshi Kawahata, Kentaro Yamaguchi,
Tópico(s)Sulfur-Based Synthesis Techniques
ResumoAbstract Nucleophilic ring‐opening reactions of 3‐aryl‐1‐benzylaziridine‐2‐carboxylates were examined by using O‐nucleophiles and aromatic C‐nucleophiles. The stereospecificity was found to depend on substrates and conditions used. Configuration inversion at C(3) was observed with O‐nucleophiles as a major reaction path in the ring‐opening reactions of aziridines carrying an electron‐poor aromatic moiety, whereas mixtures containing preferentially the syn ‐diastereoisomer were generally obtained when electron‐rich aziridines were used ( Tables 1–3 ). In the reactions of electron‐rich aziridines with C‐nucleophiles, S N 2 reactions yielding anti ‐type products were observed ( Table 4 ). Reductive ring‐opening reaction by catalytic hydrogenation of (+)‐ trans ‐(2 S ,3 R )‐3‐(1,3‐benzodioxol‐5‐yl)aziridine‐2‐carboxylate (+)‐ trans ‐ 3c afforded the corresponding α ‐amino acid derivative, which was smoothly transformed into (+)‐ tert ‐butyl [(1 R )‐2‐(1,3‐benzodioxol‐5‐yl)‐1‐methylethyl]carbamate((+)‐ 14 ) with high retention of optical purity ( Scheme 6 ).
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