Diastereoselective (Ethoxycarbonyl)difluoromethylation of Chiral Imide Enolates Mediated by Triethylborane

Katsuhiko ISEKI; Daisuke ASADA; Mie TAKAHASHI; Takabumi NAGAI; Yoshiro KOBAYASHI

doi:10.1248/cpb.44.1314

Katsuhiko ISEKI, Daisuke ASADA, Mie TAKAHASHI, Takabumi NAGAI, Yoshiro KOBAYASHI

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Keywords: (ethoxycarbonyl)difluoromethylation, asymmetric synthesis, chiral fluorinated compound, triethylborane, ethyl difluoroiodoacetate, N-acyloxazolidinone

JOURNAL FREE ACCESS

1996 Volume 44 Issue 7 Pages 1314-1317

DOI https://doi.org/10.1248/cpb.44.1314

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Abstract

Triethylborane-mediated reactions of lithium enolates derived from chiral N-acyloxazolidinones with ethyl difluoroiodoacetate allows easy access to α-(ethoxycarbonyl)difluoromethylated carboximides with good diastereomeric excess (86->98%de). The stereochemistry of the (ethyoxycarbonyl)difluoromethylated carboximides indicates that the (ethoxycarbonyl)difluoromethyl radical generated from ethyl difluoroiodoacetate and triethylborane reacts preferentially on the si face of the lithium enolates.

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