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[摘要]：Synthesis of alpha-amino ketones and O-alkyloximes has been developed by titanium tetrahalide-promoted ring-opening reactions of 2-mono-substituted azetidin-3-ones and their O-alkyloximes. Regarding the reductive ring-opening reactions of 2-mono-substituted azetidin-3-ones, an appropriate use of TiI4 or TiI4-TiCl4 as a promoter gave alpha-amino ketones in good yields with high regioselectivities. In TiBr4-promoted ring-opening reactions, while use of 2-mono-substituted azetidin-3-ones as a substrate provided alpha-amino-alpha'-bromo ketones generated by the attack of the bromide anion at the less hindered site, those of 2-mono-substituted azetidin-3-one O-alkyloximes proceeded at the more hindered site to give alpha-amino-alpha'-bromo ketone O-alkyloximes in good yields. |
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