Z-Selective Horner–Wadsworth–Emmons reaction of 2-TOM-cyclopentanone for the synthesis of rac-N-Cbz-Gly-Ψ[(Z)-CFC]-Pro-OH dipeptide isostere

The Horner–Wadsworth–Emmons reactions of 2-fluoro-2-diethylphosphonoacetic acid with 2-{[(triisopropylsilyl)oxy]methyl}cyclopentanone (2-TOM-cyclopentanone) using methylmagnesium chloride furnished the corresponding tetra-substituted fluoroolefin in a Z-selective manner (E/Z = 9:91). A facile synthesis of rac-N-Cbz-Gly-Ψ[(Z)-CFC]-Pro-OH as a dipeptide isostere was achieved based on the Z-selective Horner–Wadsworth–Emmons reaction.