Asymmetric synthesis based on (2R,3S)-3,4-dimethyl-2-phenylperhydro-1,4-oxazepine-5,7-dione. Synthesis of highly optically active .BETA.-substituted alkanoic acids.

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概要

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• A general method was worked out for the preparation of highly optically pure β-substituted alkanoic acids from aldehydes with use of (2<I>R</I>,3<I>S</I>)-6-alkylidene-3,4-dimethyl-2-phenylperhydro-1,4-oxazepine-5,7-diones(<B>2</B>) as key intermediates. Oxazepines(<B>2</B>) were prepared in high yields by treating aldehydes with (2<I>R</I>,3<I>S</I>)-3,4-dimethyl-2-phenylperhydro-1,4-oxazepine-5,7-dione(<B>1</B>) in the presence of titanium tetrachloride. The conjugate addition of Grignard reagents to <B>2</B> in the presence of nickel chloride, followed by hydrolysis and decarboxylation afforded highly enantiomerically pure β-substituted alkanoic acids in good yields. The addition of lithium dialkylcuprate to <B>2</B> was examined. It was found that (<I>S</I>)-(+)-3-phenylheptanoic acid is obtained by the reaction of lithium dibutylcuprate with (<I>E</I>)- and (<I>Z</I>)-6-benzylidene derivatives of <B>1</B>, respectively.

• 公益社団法人 日本化学会の論文

著者

• Takeda Takeshi

  Department of Chemistry, Faculty of Science, The University of Tokyo

関連論文

• Asymmetric synthesis based on (2R,3S)-3,4-dimethyl-2-phenylperhydro-1,4-oxazepine-5,7-dione. Synthesis of highly optically active .BETA.-substituted alkanoic acids.

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