Synthesis of Allyl and Alkyl Vinyl Ethers Using an in Situ Prepared Air-Stable Palladium Catalyst. Efficient Transfer Vinylation of Primary, Secondary, and Tertiary Alcohols

Abstract

An air-stable palladium catalyst formed in situ from commercially available components efficiently catalyzed the transfer vinylation between butyl vinyl ether and various allyl and alkyl alcohols to give the corresponding allyl and alkyl vinyl ethers in 61-98% yield in a single step.

Asymmetric Access to α‐Substituted Functional Aspartic Acid Derivatives by a [3+2] Strategy Employing a Chiral Dienophile

“…Importantly, in view of the analogies displayed in the NMR spectroscopic data, this also confirms the assignment of pure E geometry to 6a and to the other Nbenzyl nitrones described previously. Whereas Ishii's method [14] employing an Ir I catalyst ( Table 1, Entry 2) gave disappointing results in our hands, methods employing Au I /Ag I [15] or Pd II [16] catalysis (Table 1, Entries 3 and 4) were found to improve the yield. Preparation of nitrones 6b and 6c.…”

“…Pd(OAc) 2 , DDP, butyl vinyl ether, NEt 3 , 9 3 75°C, 24 h [16] The nitrones 6a-d and chiral dipolarophiles 7a and 7b were then subjected to thermal 1,3-DC cycloaddition conditions (toluene, 125°C, 48 h, Table 2). With N-benzyl nitrone 6a, cycloadditions occurred in high yields with vinyl ether 7a in a 86:14 trans selectivity ( Table 2, Entry 1), lower than that previously obtained with ethyl vinyl ether (92:8).…”

Flexible and biomimetic analogs of triple uptake inhibitor 4-((((3S,6S)-6-benzhydryltetrahydro-2H-pyran-3-yl)amino)methyl)phenol: Synthesis, biological characterization, and development of a pharmacophore model

“…It was noted that addition of triethylamine neutralized free acid and significantly reduced the formation of the acetal side product. 39 The reaction was carried out in a sealed tube and heated to 50 °C to force the equilibrium in the forward direction. Thus, 30 was obtained in moderate yield (50%) along with the recovery of unreacted alcohol (38%) which was recycled in the synthesis.…”

Development of Stereocontrolled Palladium(II)‐Catalyzed Domino Heck/Suzuki β,α‐Diarylation Reactions with Chelating Vinyl Ethers and Arylboronic Acids

“…The mixture was stirred at 60 °C until all solids were dissolved and a clear bright yellow solution was obtained. To prevent acetal formation,26 Et 3 N (0.69 mL, 4.97 mmol) was added before the addition of piperidine alcohol (2.90 g, 24.8 mmol) by cannula. The reaction was refluxed for 72 h or until GC–MS showed no further improvement.…”