Rhodium-Catalyzed Oxidative Decarboxylation Annulation Reactions of Mandelic Acids and Alkynes: An Efficient Synthetic Method for Indenones

Abstract

Efficient rhodium-catalyzed oxidative decarboxylation annulation reactions between mandelic acids and alkyne derivatives are described. The desired indenone products were obtained in medium to good yields under the optimized reaction conditions, which were a [RhCp*Cl2]2 catalyst (10.0 mol %) in combination with a PCy3 ligand (10.0 mol %) and AgSbF6 (10 mol %) and Cu­(OAc)2 (20 mol %) additives. Many functional groups are compatible with the reaction under the optimized reaction conditions. This strategy provides a promising method for the construction of indenones from cheap and commercially available starting materials.

Rh(III)-Catalyzed Diastereodivergent Spiroannulation of Cyclic Imines with Activated Alkenes

“…Metal-catalyzed C–H activation and functionalization has provided important approaches for step-economic synthesis of various drug-related chemicals and organics . Among these, tandem [3 + 2] annulation reactions between readily available arenes and unsaturated bonds have been widely investigated. − This type of reaction involves a C–H bond activation process followed by in situ transformations of the directing group, which offers a straightforward route to access cyclic compounds and is especially useful for the construction of spirocycles that are otherwise difficult to synthesize. − …”

Divergent Synthesis of α-Aroyloxy Ketones and Indenones: A Controlled Domino Radical Reaction for Di- and Trifunctionalization of Alkynes

“…5-Methyl-2,3-diphenyl-1H-inden-1-one (4a): 21 orange solid; yield 68% (20 mg); R f = 0.41 (silica gel, hexane/EtOAc 95:5); 1 H NMR (500 MHz, CDCl 3 ) δ 2.36 (s, 3H), 6.95 (s, 1H), 7.09 (d, J = 7.2 Hz, 1H), 7.22−7.30 (m, 5H), 7.37−7.45 (m, 5H), 7.49 (d, J = 7.2 Hz, 1H); 13 C{ 1 H} NMR (125 MHz, CDCl 3 ) δ 22.1, 122.5, 123.0, 127.6, 128.0, 128.4, 128.5, 128.8, 128.9, 129.1, 130.0, 130.9, 132.8, 132.9, 144.4, 145.7, 154.9, 196.1; EI-MS m/z 296 (M •+ , 100), 281 (53), 265 (16), 252 (48), 216 (14), 189 (12), 126 (14). Anal.…”

“…2,naphthalen-1-one (4f): 25 orange solid; yield 42% (14 mg); R f = 0.42 (silica gel, hexane/EtOAc 95:5); 1 H NMR (500 MHz, DMSO-d 6 ) δ 7. 13−7.19 (m, 4H), 7.36−7.44 (m, 3H) 8, 123.1, 125.6, 126.3, 126.5, 127.0, 127.2, 128.4, 129.0, 129.1, 129.4, 129.8, 130.0, 130.8, 131.1, 133.1, 133.8, 134.8, 146.3, 155.2, 196.2; EI-MS m/z 332 (M •+ , 100), 316 (19), 303 (48), 282 (21), 255 (21), 155 (21), 141 (22), 127 (19). Anal.…”

Ligand‐Promoted Rhodium(III)‐Catalyzed ortho‐C−H Amination with Free Amines

“…Ther eaction is initiated by the coordination of amide 1i to aR h III species bound to the quinoline ligand (L), which is followed by CÀHa ctivation to give the corresponding fivemembered rhodacycle intermediate 7.S ubsequent ligand exchange at the Rh III center leads to intermediate 8,w hich undergoes C À Nr eductive elimination to give the orthoaminated product 3i and aR h I species.S uch al igand exchange process has also been observed with phosphine ligands. [15] Theo xidation of Rh I by Ag 2 CO 3 completes the catalytic cycle.…”