Formal α-Allylation of Primary Amines by a Dearomative, Palladium-Catalyzed Umpolung Allylation of N-(Aryloxy)imines

Abstract

N-(Aryloxy)­imines, readily accessible by condensation/tautomerization of (pseudo)­benzylic primary amines and 2,6-di-tert-butyl-1,4-benzoquinone, undergo efficient allylation to afford a wide range of homoallylic primary amines following hydrolytic workup. Deprotonation of N-(aryloxy)­imines generates a delocalized 2-azaallyl anion-type nucleophile that engages in dearomative C–C bond-forming reactions with allylpalladium­(II) electrophiles generated from allylic tert-butyl carbonates. This reactivity umpolung enables the formal α-allylation of (pseudo)­benzylic primary amines. Mechanistic studies reveal that the apparent regioselectivity of the desired bond-forming event is a convergent process that is initiated by unselective allylation of N-(aryloxy)­imines to give several regioisomeric species, which subsequently rearrange via stepwise [1,3]- or concerted [3,3]-sigmatropic shifts, ultimately converging to provide the desired regioisomer of the amine products.

Alkali–Amide-Catalyzed One-Pot Aminoallylation of Aldehydes with Allylbenzenes

“…13 C­{ 1 H} NMR (101 MHz, CDCl 3 ) δ: 162.2 (d, J 1 C‑F = 246.2 Hz), 145.8, 133.6 (d, J 4 C‑F = 3.2 Hz), 131.7, 128.6, 127.6 (d, J 3 C‑F = 7.9 Hz), 127.2, 126.9 (d, J 4 C‑F = 1.9 Hz), 126.4, 115.5 (d, J 2 C‑F = 21.5 Hz), 55.9, 43.5 ppm. The spectroscopic data for this product match the literature data …”

“…13 C­{ 1 H} NMR (101 MHz, CDCl 3 ) δ: 145.8, 135.9, 132.8, 131.7, 128.8, 128.6, 127.9, 127.4, 127.2, 126.4, 55.9, 43.5 ppm. The spectroscopic data for this product match the literature data …”

“…The spectroscopic data for this product match the literature data. 28 (E)-4-(4-Chlorophenyl)- 1-phenylbut-3-en-1-amine (3aj). The reaction was performed following General Procedure A with benzaldehyde (1a) (21.2 mg, 0.2 mmol), NaN(SiMe 3 ) 2 (44.0 mg, 0.24 mmol), 1-allyl-4-chlorobenzene (2j) (60.8 mg, 0.4 mmol), and dry THF (1.0 mL).…”

Exploiting Iminoquinones as Electrophilic at Nitrogen “N+” Synthons for C–N Bond Construction

“…Our research group has developed several quinone-catalyzed or quinone-mediated transformations for the synthesis of amine derivatives. During the development of a stepwise umpolung approach for the α-allylation of benzylic amines with allylpalladium species, we observed that iminoquinones derived from 3-butenylamines underwent cyclization by intramolecular C–N bond formation, leading to pyrrole products in low yields (see the Supporting Information). Importantly, control experiments ruled out the intervention of Pd as a catalyst.…”