Synthesis and Reactions of 2-Alkoxy-1, 1, 3, 3, 3pentafluoropropenes as a Synthon for Trifluoromethylated Compounds

Abstract

1, 1, 3, 3, 3-Pentafluoropropenesh aving a tetrahydropyrany l oxyl or methoxyethoxymethoxyl group at 2-position ([2a], [2b]) were prepared as synthons for t rifluoromethylated c ompounds.
The addition of alkoxides, amides or alkanides anion to [2 a] or[2b] followed by elimination of fluoride anion afforded the Correspondingo lefines[3] .
Trifluorolactamides [ 5 D] were prepared by the addition-eli m ination reaction of [2a ] with amide anions and the subsequent hydrolysis. When lithium (S)-(-)-1-phenylethylam ide was used, the reaction products, trifluorolactamides [ 6 ] were separated into two epimers and their configurations were determined by X-ray analysis and other methods.
Furthermore, 2-hydroxy-2-trifluoromethy1-4-alkenoica cids [10] a nd t h eir esters [11] were prepared via the addition-elimination of [2a ] or [2b] with allylic alkoxidesa nd the s ubseq uent. [3, 3]-sigmatropic rearrangement.