Direct β‐Activation of Saturated Aldehydes to Formal Michael Acceptors through Oxidative NHC Catalysis

Organocatalytic Reactions Enabled by N-Heterocyclic Carbenes

“…207 For comparison, in the canonical oxidative NHC pathway, an enal first reacts with the free carbene to form an extended Breslow intermediate 181 . The latter is then oxidized to the α,β-unsaturated acylazolium ion 182 with aid of a mild organic oxidant.…”

Selective Radical–Radical Cross-Couplings: Design of a Formal β-Mannich Reaction

“…1 In contrast, the direct β -functionalization of saturated carbonyl compounds represents an important challenge in organic synthesis that has attracted considerable interest from the chemical community over the past few years. 3,4 In this context, our laboratory recently disclosed the 5 π -electron (5 π e − ) activation mode for the direct β -arylation of saturated formyl and ketone systems (eq 1). 4a More specifically, the synergistic merger of organocatalysis and photoredox catalysis enables the efficient coupling of two catalytically generated species, a 5 π e − β -enaminyl radical, generated via single-electron oxidation of an enamine, and a persistent cyanoarene radical anion, formed by single-electron reduction of aryl nitriles.…”

N-Heterocyclic carbene-catalyzed annulation of cyclic β-enamino esters with enals: access to functionalized indolo[2,3-a]quinolizidines

“…1 H NMR (300MHz, CDCl 3 ): δ 12.25 (brs, 1H), 7.61 (d, J = 8.0, 1H), 7.49 (d, J = 8.3 Hz, 1H), 7.14-7.37 (m, 7H), 5.21 (m,1H),4.53 (dd,J = 5.4,3.2 Hz,1H), 3.81 (s, 3H), 3.25 (m, 1H), 2.96-3.04 (m, 4H). 13 C NMR (75MHz, CDCl 3 ): δ 169. 2,168.7,142.2,140.2,136.9,128.8,127.0,126.6,125.8,125.4,124.9,120.1,119.5,119.2,112.2,107.7,52.5,40.9,38.8,37.8,20.9.…”

“…1 H NMR (300MHz, CDCl 3 ): δ 12.27 (brs, 1H), 7.58 (d, J = 8.0 Hz, 1H), 7.47 (d,J = 8.3Hz,1H),7.34 (m,1H),2H),2H),7.07 (m,1H),5.21 (m,1H),4.48 (dd,J = 6.0,2.4 Hz,1H), 3.80 (s, 3H), 3.21 (m, 1H), 2.90-3.03 (m, 2H), 2.85-2.97 (m, 2H). 13 C NMR (75MHz, CDCl 3 ): δ 168. 9, 168.4, 142.7, 142.4, 137.0, 134.7, 130.1, 127.3, 127.0, 125.7, 125.6, 124.9, 124.8, 120.2, 119.6, 119.5, 112.3, 106.9, 52.6, 41.0, 38.8, 37.8, 21.0 1695,1668,1593,1560,1516,1367,1332,1282,1255,1205,1178,1157,1122 3, 168.9, 142.2, 139.9, 138.3, 136.9, 128.6, 127.9, 127.5, 125.9, 125.4, 125.0, 123.6, 120.1, 119.5, 119.1, 112.2, 107.9, 52.6, 40.9, 38.9, 37.8, 21.5, 21.0 1689,1670,1558,1510,1369,1330,1282,1261,1220,1205,1188,1172,1124,748 (d, J = 8.0 Hz, 1H), 7.48 (d, J = 8.3 Hz, 1H), 7.26-7.36 (m, 3H), 7.…”

“…3H),5.21 (m,1H),4.48 8.7,5.4 Hz,1H),2H),3H), 7.12 (dd, J = 9.6, 2.1 Hz, 1H), 6.91 (m, 1H), 5.20 (m, 1H), 4.51 (m, 1H), 3.78 (s, 3H), 3.19 (m, 1H), 2.94-2.99 (m, 4H). 13 C NMR (75MHz, CDCl 3 ): δ 169. 3,168.8,161.9 (d,1C), 142.0, 140.1, 137.0 (d, J C-F = 13.0 Hz, 1C), 128.…”