Barma DK, Kundu A, Zhang H, Mioskowski C, Falck JR. (Z)-alpha-haloacrylates: an exceptionally stereoselective preparation via Cr(II)-mediated olefination of aldehydes with trihaloacetates.
J Am Chem Soc 2003;
125:3218-9. [PMID:
12630869 DOI:
10.1021/ja029938d]
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Abstract
(Z)-alpha-Fluoro-, (Z)-alpha-chloro-, and (Z)-alpha-bromoacrylates were obtained with unprecedented yield and stereocontrol (>99%) via addition of the corresponding commercial trihaloacetates to aldehydes at room temperature using stoichiometric Cr(II) salts or catalytic Cr(II) with a regeneration system. The intermediate 2,2-dihalo-3-hydroxy adducts could be isolated in good yields under conditions of limited reagent at 0 degrees C.
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