Allenes. Part 36. Synthesis of 2,4,5-trienamides as potential insecticides, by a Wittig reaction

Abstract

N-Substituted 2,4,5-trienamides have been synthesised by the reactions of a 4,4-dialkylbuta-2,3-dienal with diethyl N-alkyl-and NN-dialkylcarbamoylmethylphosphonates, and characterised by i.r., u.v., and n.m.r. spectra. An attempted Wittig reaction of hepta-2.3-dienal and diethyl N-isobutylcarbamoylmethylphosphonate resulted in mainly nucleophilic attack a t C-3 of the allenic aldehyde.

Enantioselective Total Synthesis of (+)-U-106305

“…The desired alcohol 3 was isolated in 92% yield for the two steps after desilylation. PDC oxidation and Horner−Emmons−Wadsworth olefination with diethyl (( N -isobutylcarbamoyl)methyl)phosphonate produced (+)-U-106305. The synthetic and natural material were identical in all respects ( 1 H NMR, 13 C NMR, HPLC, HRMS) except that the sign of the optical rotation of the synthetic material was opposite to that of the natural material .…”

Synthesis of the Enantiomers of Hexahydrodibenz[d,f]azecines

“…Further elaboration of biphenyls 11 and 12 to the target compounds 3 and 4 is also illustrated in Scheme 2. Chain extension by use of the Horner−Emmons reagent, diethyl N- methylphosphonoacetamide, gave compounds 13 and 14 in 98 and 79% yields, respectively, and hydrogenation of these enamides over Raney nickel afforded the dihydro adducts 15 and 16 quantitatively. Reaction of these amides with lithium aluminum hydride in dry THF gave the corresponding amines, which were treated with di- tert -butyl dicarbonate and triethylamine to yield the N-protected amines 17 and 18 with modest efficiency (38% and 48%, respectively).…”

Synthesis and Properties of Oligocyclopropyl-Containing Natural Products and Model Compounds

“…After deprotection the key intermediate 100 was isolated in high yield. PDC oxidation and chain elongation with diethyl ( N -isobutylcarbamoyl)methylphosphonate furnished (+)-U-106305 ( ent - 2 ). While all spectroscopic data of the natural and the synthetic compounds were identical, the sign of the optical rotation was opposite.…”