- An expedient access to still-gennari phosphonates
-
An inexpensive and efficient route to the Still-Gennari phosphonates, methyl and ethyl bis(2,2,2-trifluoroethyl)phosphono acetates, has been developed. This short reaction sequence is operationally simple and makes these versatile reagents for the prepara
- Messik, Frauke,Oberthuer, Markus
-
-
Read Online
- A Straightforward, Purification-Free Procedure for the Synthesis of Ando and Still-Gennari Type Phosphonates
-
Z-Selective Still-Gennari and Ando modifications of the typically E-selective Horner-Wadsworth-Emmons reaction are highly valuable synthetic tools in organic chemistry. These procedures are based on application of bis(2,2,2-trifluoroethyl) phosphonates or diaryl phosphonates, respectively, for the olefination of carbonyl groups. In our research, we present an improved, straightforward, purificationfree procedure for the synthesis of these reagents. The key step of our procedure is the reaction of phosphonic dichlorides with the appropriate sodium alkoxides, which results in 52-97% isolated yields of the desired products on a gram scale. The whole three-step process is performed in one pot. Most importantly, the product is obtained in over 95% purity after simple extraction, avoiding column chromatography and distillation. Moreover, we present the synthesis of a novel Still-Gennari type reagent, bis(1,1,1,3,3,3-hexafluoroisopropyl) phosphonates, which may exhibit improved Z-selectivity in Still-Gennari olefinations.
- Janicki, Ignacy,Kie?basiński, Piotr
-
p. 378 - 382
(2021/10/21)
-
- A convenient method for the synthesis of bis-trifluoroethyl phosphonoacetates
-
Bis-trifluoroethyl phosphonoacetates were easily obtained by condensation of bis-trifluoroethyl alkylphosphonates with alkyl chloroformates in the presence of 2 equivalents of lithium hexamethyldisilazane (LiHMDS).
- Patois,Savignac,About-Jaudet,Collignon
-
p. 2391 - 2396
(2007/10/02)
-