A new approach to the synthesis of (Z)-2-fluoro-2-alkenals via Wittig-type carbonyl condensation reactions of 2-(fluoromethyl)-4,4,6-trimethyl-1,3-oxazine phosphonium bromide

作者：Kajjout Mohammed; Smietana Michael; Leroy Jacques; Rolando Christian^*

来源：Tetrahedron Letters, 2013, 54(13): 1658-1660.

DOI：10.1016/j.tetlet.2013.01.017

• 2-Fluoro-2-alkenals
• Oxazine
• Phosphonium salt

We report here the transformation of aldehydes to their (Z)-alpha-fluoro-alpha,beta-unsaturated aldehyde homologs by condensation with the phosphonium salt of the Meyer%26apos;s oxazine obtained from bromofluoroacetonitrile. After methylation with trimethyloxonium tetrafluoroborate the quaternized oxazine is cleanly reduced to mostly Z 2-fluoro-2-alkenals by sodium borohydride at room temperature. This methodology is compatible with usual protecting groups and affords an efficient access to functionalized mostly Z 2-fluoro-2-alkenals derived from natural products and their corresponding (Z)-2-fluoro-2-alkenols.

• 出版日期2013-3-27