Recent topics of the natural product synthesis by Horner–Wadsworth–Emmons reaction

Total synthesis of nahuoic acid A via a putative biogenetic intramolecular Diels–Alder (IMDA) reaction

“…In addition, model pentaenals 34a and 34b were constructed by unsaturated chain extension of iodotrienal 19 . 19 The Horner–Wadsworth–Emmons (HWE) reaction 28 of 19 (ref. 19 ) with the corresponding anions of phosphonates 30a and 30b , generated with n -BuLi and DMPU in THF, afforded conjugated dienoates 31a and 31b , respectively ( Scheme 4 ), whereas the reaction with phosphonate 30a afforded a 5 : 1 E / Z mixture of isomers of 31a in 77% yield, and using the methyl-substituted analogue 30b both the isomer ratio (10 : 1) of pentaenoate 31b and the yield of the HWE reaction (89%) were higher.…”

“…Unfortunately, all attempts to perform the unsaturated chain extension of aldehyde Si-exo 35 either using the HWE reaction 28 with phosphonate 30b ( Scheme 4 , by heating up to 40 °C), the Wittig reaction 28 a ,33,34 with the phosphonium salt analogue or the less-sterically demanding Peterson olefination 35 with the trialkylsilyl derivative as the reagent, proved to be fruitless, and the alkenyloctahydronaphthalene carboxaldehyde Si-exo 35 was recovered.…”

1-Aminoalkylphosphonium Derivatives: Smart Synthetic Equivalents of N-Acyliminium-Type Cations, and Maybe Something More: A Review

“…As demonstrated by Mazurkiewicz and Kuźnik, N -acyl-1-triphenylphosphonioglycinate tetrafluoroborates 91 are also convenient starting compounds for the transformation into N -acyl-α-(dialkoxyphosphoryl)glycinates 108 by the Michaelis–Arbuzow-type reaction with trimethylphosphite in the presence of methyltriphenylphosphonium iodide as a catalyst ( Scheme 32 ) [ 89 ]. Among others, α-(dialkoxyphosphoryl)glycinates became the crucial synthetic tool commonly used for the synthesis of many natural products (including β-lactam antibiotics) or α,β-dehydro-α-amino acids by the Wadsworth-Emmons reaction [ 90 , 91 , 92 , 93 , 94 , 95 , 96 ]. As is known, hydrogenation of the latter compounds using chiral catalysts is considered to be one of the most general methods for the enantioselective synthesis of α-amino acids, including non-proteinogenic α-amino acids of diverse biological activities [ 97 , 98 , 99 , 100 ].…”

Tailor‐Made Amino Acids in Pharmaceutical Industry: Synthetic Approaches to Aza‐Tryptophan Derivatives

“…To undertake Horner‐Wadsworth‐Emmons olefination, [74] the starting substrates, 3‐formylindazoles 72 was prepared by the reduction of corresponding N ‐methoxy‐ N ‐methylamides with LiAlH 4 in THF [75] . The obtained 3‐formylindazoles 72 have been suitably protected at N ‐1 position as tert ‐butyloxycarbonyl derivatives 73 and subsequently converted into dehydro 2‐AW 75 by Horner‐Wadsworth‐Emmons reaction with N ‐Cbz‐(dimethoxyphosphinyl)glycine methyl ester 74 (Scheme 15).…”