On the stereochemistry of the Horner-Emmons reaction between 3-functionally substituted 2-methyl-2-propenylphosphonates and aliphatic aldehydes 7. Quaternary ammonium phase transfer catalysts in a stereoselective synthesis of esters of 3-methyl-2E,4E-alkadienoic acids

Article abstract of DOI:10.1007/BF00704196

The reaction of diethyl 3-ethoxycarbonyl-2-methyl-2-propenylphosphonate (1a) with 3-methylbutanal (2) in heterogeneous MOH (solid)-behzene systems in the presence of 5-10 mol.percent of benzyltriethylammonium chloride (BTEAC) gives the reaction product (3) with a higher, for M = K, or lower, for M = Li, ratio of 2E,4E- and 2Z,4E-stereoisomers than that observed in the absence of BTEAC.Tetrabutylammonium bromide (TBAB) as a catalyst of the reaction 1a + 2 -> 3 in the system KOH (solid) - wet benzene leads to a higher <2E,4E-3>:<2Z,4E-3> ratio than BTEAC; this ratio grows from 44:56 without TBAB to 80:20 at 100 mol.percent of TBAB.In the latter case...