Rhodium(iii)-catalyzed annulation of enamides with sulfoxonium ylides toward isoquinolines

Abstract

An efficient rhodium(iii)-catalyzed C–H activation followed by intermolecular annulation between enamides and sulfoxonium ylides has been developed.

Ru-catalyzed C–H activation/cyclization of oximes with sulfoxonium ylides to access isoquinolines

“…The synthetic application value of this protocol was demonstrated (Scheme 4). 13 Based on relevant reports, 20,21,23 a plausible mechanism for the C-H activation/annulation process of 1a with 2a was proposed, as depicted in Scheme 5. The active cationic Ru(II) species A is generated from [RuCl 2 ( p-cymene)] 2 and AgBF 4 via Scheme 2 Scope of the acetophenone O-methyl oximes.…”

“…Methyl-3-phenylisoquinoline (3a). 21 28.9 mg (66%), yellow oil, (R f = 0.35, V EA /V PE = 4 : 96), 1 H NMR (400 MHz, CDCl 3 ) δ 8.14 (t, J = 7.0 Hz, 3H), 7.92 (s, 1H), 7.86 (d, J = 8.1 Hz, 1H), 7.67 (t, J = 7.4 Hz, 1H), 7.57 (t, J = 7.5 Hz, 1H), 7.51 (t, J = 7.4 Hz, 2H), 7.41 (t, J = 7.2 Hz, 1H), 3.05 (s, 3H). 13 C NMR (101 MHz, CDCl 3 ) δ 158.6, 150.0, 139.9, 136.8, 130.0, 128.7, 128.3, 127.6, 127.0, 126.8, 126.6, 125.6, 115.2, 22.7.…”

α-Carbonyl sulfoxonium ylides in transition metal-catalyzed C–H activation: a safe carbene precursor and a weak directing group

“…In another chemodivergent protocol independently by Yu 41a and Zhang 41b groups, the formation of fused tricyclic [1,3] Enamides are considered valuable building blocks in organic synthesis having tunable reactivity and potential use in various transformations. Zhang and coworkers 43 reported the synthesis of isoquinolines 106 via Rh(III)-catalyzed C-H activation and annulation between enamides 105 and sulfoxonium ylides 2 (Scheme 39). This additive-free protocol facilitated a range of diverse 1,3-disubstituted isoquinolines with moderate to good yields under mild conditions.…”

Free Amine-Directed Ru(II)-Catalyzed Redox-Neutral [4 + 2] C–H Activation/Annulation of Benzylamines with Sulfoxonium Ylides

“…5, 140.7, 136.3, 136.1, 130.7, 130.0, 129.9, 127.9, 127.4, 126.8, 126.0, 125.8, 125.6, 118.7, 22.4, 20.5. 3-(2-Methoxyphenyl)-1-methylisoquinoline (3aq). 24 The crude product was purified by silica gel column chromatography using a of gradient 0−7% (EtOAc/n-hexane) to afford 3aq as a yellow solid (55.0 mg, 74%); 1 H NMR (500 MHz, CDCl 3 ): δ 8.14 (d,J = 8.4 Hz,1H), 8.05 (s, 1H), 7.91 (d,J = 7.4 Hz,1H), 7.85 (d, J = 8.1 Hz, 1H), 7.68 (t, J = 7.4 Hz, 1H), 7.59 (t, J = 7.6 Hz, 1H), 7.39 (t, J = 11.4, 4.1 Hz, 1H), 7.12 (t, J = 7.4 Hz, 1H), 7.04 (d,J = 8.3 Hz,1H),3.89 (s,3H), 3.08 (s, 3H); 13 C{ 1 H} NMR (125 MHz, CDCl 3 ): δ 157.9, 157.2, 147.3,136.4,131.4,130.2,129.5,128.6,127.7,126.9,126.2,125.5,121.0,120.1,111.6,55.7,-1-methylisoquinoline (3ar). 11 The crude product was purified by silica gel column chromatography using a of gradient 0−5% (EtOAc/n-hexane) to afford 3ar as a yellow solid (56.0 mg, 73%); 1 H NMR (500 MHz, CDCl 3 ): δ 8.16 (d,J = 8.3 Hz,1H),2H),2H),1H), 7.51 (d, J = 7.9 Hz, 1H), 7.39 (td, J = 7.5, 1.0 Hz, 1H), 7.33 (td, J = 7.7, 1.7 Hz, 1H), 3.04 (s, 3H); 13 C{ 1 H} NMR (125 MHz, CDCl 3 ): δ 158.…”