Improved Horner-Wadsworth-Emmons preparation of α-methyl-or α-ethyl-α,β-unsaturated esters from aldehydes
2001
Petroski, Richard J. | Weisleder, David
The E-isomer selectivity of the Horner-Wadsworth-Emmons olefination of aldehydes to form α-methyl- or a-ethyl-α,β-unsaturated esters has been improved by using lithium tert-butoxide as the base, triethyl-2-phosphonopropionate or triethyl-2-phosphonobutyrate as the phosphonate, an aldehyde, and hexane as the reaction solvent. Greater E-isomer selectivity was observed in the formation of α-methyl-α,β-unsaturated esters than α-ethyl-α,β-unsaturated esters. These compounds are useful intermediates for the synthesis of insect pheromones and natural products.
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