Catalytic Allylation of Stabilized Phosphonium Ylides with Primary Allylic Amines

Abstract

A range of ketone-stabilized phosphonium ylides were allylated with high regioselectivity by primary allylic amines in the presence of 5 mol % Pd(PPh3)4 and 10 mol % B(OH)3, and subsequent one-pot Wittig olefination gave structurally diverse α,β-unsaturated ketones in good to excellent overall yields with excellent E selectivity. The one-pot allylation/olefination reaction was extended to ester- and nitrile-stabilized phosphonium ylides by replacing B(OH)3 with TsOH, and the corresponding α,β-unsaturated esters and nitriles were obtained in moderate overall yields.

Transition metal-catalyzed allylic substitution reactions with unactivated allylic substrates

“…92 Boric acid activates the NH 2 group of the chiral amine 91 and the allylic C-N bond is cleaved by the Pd(0) catalyst with inversion of configuration to give p-allylpalladium 94a. 94 A number of ketone-stabilized phosphonium ylides were allylated with high regioselectivity using a catalyst system consisting of 5 mol% Pd(PPh 3 ) 4 and 10 mol% B(OH) 3 . Alternatively, the Pd atom of complex 94a is attacked by sulfonate 92 to from the Pd-S-sulfinate 96a, which undergoes reductive elimination to give the minor enantiomer ent-93 (path B).…”

Towards Supramolecular Catalysis with Small Self‐assembled Peptides

“…Indeed, increasing the catalyst loading to 1 mol % and elevating the temperature to 100 °C (oil bath) permitted the allylation of H ‐phosphinic acid 4 a with primary allylic amine 1 a to take place in tertiary amyl alcohol, albeit the desired product, disubstituted phosphinic acid 5 a , was obtained in only 34 % yield (Table 3, entry 1). Inspired by our previous findings,3a,b,d we added 1.2 equivalents of boric acid to the reaction mixture and found that the yield improved to 75 % (Table 3, entry 2). Whereas replacing tertiary amyl alcohol with another common solvent failed to improve the yield (Table 3, entries 3–7), we surveyed a few Brønsted acids and found that the use of aqueous phosphoric acid improved the yield to 94 % (Table 3, entry 10).…”

“…Moreover, the basicity of allylic amines permits their purification in large quantities by simple extractive procedures instead of routine chromatography. Sporadic studies have shown that allylic amines, in most cases secondary and tertiary ones, can undergo the Tsuji–Trost reaction with a few types of carbon,3b–d, 4 nitrogen,5 and sulfur nucleophiles 3a,e. 6, 7 To the best of our knowledge, there is no previous report on the Tsuji–Trost reaction of allylic amines with phosphorus nucleophiles.…”

Catalytic C−C Bond Formation Using a Simple Nickel Precatalyst System: Base‐ and Activator‐Free Direct C‐Allylation by Alcohols and Amines

“…Thoughp alladium-mediated processes are well-known, [16] there are no reports of ag eneral methodf or nickel-catalysed allylation reactions using allyl amines. [10] We were gratified, therefore, to observe that our method was also productive when using N,N-diethyl allylamine or allylamine itself as a pallyl precursor( Ta ble 4).…”