Two approaches for the synthesis of fluorinated (F) and nonfluorinated (H) 4-(alkoxycarbonyl)-substituted cis- and transvinyldiazocarbonyl compounds with substituents of variable stereoelectronic nature (H, Me, Ph, CF3, OTBS) at the C-3 atom of the vinyldouble bond from the relevant 1,3-dicarbonyl compounds were compared: a pathway using the Wittig reaction followed by a diazo transfer reaction was most efficient for the synthesis of the H-vinyldiazocarbonylcompounds (total yields of up to 60%), while the yields of their F-analogues under similar conditions did not exceed 16–37%. An approach via diazo transfer followed by the Wittig reaction,in contrast, is more effective for the preparation of F-vinyldiazocarbonyl compounds (total yields 37–69%). The configuration of the resulting F- and H-vinyldiazocarbonyl compounds is evidently controlled by the steric bulk of the substituent at the C-3 atom of the vinyl double bond and, in addition, depends on the specific synthetic pathway.
Supurgibekov, M. B., Prakash, G. K. S., & A.Nikolaev., V. (2013). Synthesis and stereochemistry of fluorinated and non-fluorinated 4-alkoxycarbonyl-2-vinyldiazocarbonyl compounds. Synthesis, 45(9), 1215–1226. https://doi.org/DOI: 10.1055/s-0032-1318309