Tetrahedron

An improved procedure for the lateral lithiation of ethyl 4-acetyl-5-methyl-3-isoxazolyl carboxylate

DJ Burkhart, P Zhou, A Blumenfeld, B Twamley…

Index: Burkhart, David J.; Zhou, Peiwen; Blumenfeld, Alex; Twamley, Brendan; Natale, Nicholas R. Tetrahedron, 2001 , vol. 57, # 38 p. 8039 - 8046

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Citation Number: 17

Abstract

Ethyl 4-acetyl-5-methyl-3-isoxazolyl carboxylate was smoothly lithiated at the 5-methyl position, when the 4-acetyl group was protected with a 5, 5-dimethyl-1, 3-dioxanyl group. The lithio anion was quenched with a variety of electrophiles such as alkyl halides, aldehydes, TMSCl, and Me3SnCl in good to excellent yields. The lithiation of the unprotected compound and the 4-acetyl group protected as 1, 3-dioxolanyl both failed. ...