Redox‐Neutral α‐Allylation of Amines by Combining Palladium Catalysis and Visible‐Light Photoredox Catalysis

Abstract

An unprecedented α-allylation of amines was achieved by combining palladium catalysis and visible-light photoredox catalysis. In this dual catalysis process, the catalytic generation of allyl radical from the corresponding π-allylpalladium intermediate was achieved without additional metal reducing reagents (redox-neutral). Various allylation products of amines were obtained in high yields through radical cross-coupling under mild reaction conditions. Moreover, the transformation was applied to the formal synthesis of 8-oxoprotoberberine derivatives which show potential anticancer properties.

Recent advances in dual transition metal–visible light photoredox catalysis

“…36 Recently, efficient α-allylation of tetrahydroisoquinolines (20) and other amines was realized by Lu and Xiao (Figure 8). 37 In this synergistic Pd-Ir dual catalysis, the THIQ is oxidized to form α-amino alkyl radical by the photocycle and after the one electron reduction of π-allylpalladium complex the separately formed radicals are recombined by a radical cross-coupling step, which provides the corresponding product. 5 mol% of Pd(PPh 3 ) 4 and 2 mol% Ir[(ppy) 2 (dtbbpy)]PF 6 was used as catalysts.…”

Visible-Light-Initiated Na2-Eosin Y Catalyzed Highly Regio- and Stereoselective Difunctionalization of Alkynes with Alkyl Bromides

“…6, 130.4, 129.8, 129.3, 128.7, 128.3, 121.0, 112.2, 111.2, 60.9, 40.6, 27.8 (E)-2-(2-Bromo-2-(4-methoxyphenyl)vinyl)-2-((2,5-dioxopyrrolidin-1-yl)(phenyl)methyl)malononitrile (3ab). Following the general procedure, the product was isolated as a white solid: 144.5 mg (78%); mp = 133−134°C; 1 H NMR (400 MHz, CDCl 3 ) δ 7.71 (d,J = 7.2 Hz,2H),3H),7.35 (d,J = 8.4 Hz,2H),6.93 (d,J = 8.4 Hz, 2H), 6.13 (s, 1H), 5.58 (s, 1H), 3.82 (s, 3H), 2.79 (s, 4H); 13 C NMR (100 MHz, CDCl 3 ) δ 176. 1, 161.3, 132.3, 131.4, 130.5, 130.2, 129.9, 129.4, 128.0, 120.6, 114.2, 112.5, 111.4, 61.0, 55.3, 40.7, 28. 141.0, 132.9, 132.2, 131.3, 130.4, 129.8, 129.3, 129.3, 128.3, 120.6, 112.3, 111.3, 60.9, 40.6, 27.8, 21.4; HRMS (ESI) calcd for C 23 H 18 BrN 3 O 2 Na (M + Na) + 470.0480; found 470.0472.…”

“…90−7.88 (m, 2H), 7.77−7.75 (m, 4H), 7.44−7.42 (m, 8H), 6.34 (s, 1H), 5.83 (s, 1H); 13 C NMR (100 MHz, CDCl 3 ) δ 167. 1,135.8,134.8,132.0,131.7,130.9,130.6,130.2,129.6,129.2,128.7,128.3,124.1,121,0,112.2,111.4,60.4,41.1;HRMS (ESI) (d,J = 8.4 Hz,2H),6.29 (s,1H),5.83 (s,1H), 3.79 (s, 3H); 13 C NMR (100 MHz, CDCl 3 ) δ 167. 1, 161.1, 134.8, 132.5, 131.8, 130.9, 130.2, 130.1, 129.6, 129.2, 128.0, 124.1, 120.5, 114.1, 112.4, 111.6, 60.4, 55.2, 41.1; HRMS (ESI) calcd for C 27 H 18 BrN 3 O 3 Na (M + Na) + 534.0429; found 534.0421.…”

“…Following the general procedure, the product was isolated as a white solid: 157.6 mg (75%); mp = 157−159°C; 1 H NMR (400 MHz, CDCl 3 ) δ 7.91−7.89 (m, 2H), 7.78−7.76 (m, 2H), 7.73 (d,J = 8.4 Hz,2H), 7.35 (d, J = 8.0 Hz, 2H), 7.26 (d, J = 8.0 Hz, 2H), 6.97 (d, J = 8.4 Hz, 2H), 6.30 (s, 1H), 5.80 (s, 1H), 3.82 (s, 3H), 2.38 (s, 3H); 13 C NMR (100 MHz, CDCl 3 ) δ 167.2, 160. 9, 141.0, 134.9, 133.1, 132.4, 131.3, 131.0, 129.5, 128.4, 124.1, 123.7, 120.9, 114.5, 112.6, 111.7, 60.3, 55.3, 41.4, 21.5; HRMS (ESI) calcd for C 28 H 20 BrN 3 O 3 Na (M + Na) + 548.0568; found 548.0577.…”

“…Following the general procedure, the product was isolated as a white solid: 119.6 mg (64%); mp = 128−130°C; 1 H NMR (400 MHz, CDCl 3 ) δ 7.69 (d, J = 7.2 Hz, 2H), 7.48−7.43 (m, 3H), 7.40(d, J = 8.4 Hz, 2H), 7.29 (d, J = 8.4 Hz, 2H), 6.22 (s, 1H), 5.58 (s, 1H), 2.79 (s, 4H); 13 C NMR (100 MHz, CDCl 3 ) δ 176.…”