Dearomatization of Fused Arenes Using Platinum‐Catalyzed Intramolecular Formation of Two CC Bonds

Abstract

Scheme 3. Possible mechanism for the formation of 2 from 1. Scheme 4. Platinum-catalyzed reaction of [D 5 ]-1 a. Scheme 5. Platinum-catalyzed reaction of 1 a in the presence of CD 3 OD. Scheme 6. Platinum-catalyzed reaction of 1 m with a trifluoromethyl substituted electron-deficient benzyl group. Scheme 7. Hydrogenation of dearomatized product 2 a. Angewandte Chemie 6325

Platinum-Catalyzed Intramolecular Spirocyclization of N-(Methylnaphthalenyl)propiolamides via Formal Aromatic Ene Reaction

“…14 When using N-benzyl-N-(naphthalen-1yl)propiolamides and a cationic platinum(II) complex, the catalytic dearomative intramolecular 6-endo cyclization through CC bond formation at the ipso and ortho positions of the acylamino group proceeded in high yields (Figure 2a, bottom). 15,16 In this paper, we disclose the platinum(II)catalyzed intramolecular dearomative spirocyclization (5-endo cyclization) of N-(methylnaphthalenyl)propiolamides via the deprotonation−protonation sequence [formal aromatic ene reaction (Figure 2b)]. Importantly, in this transformation, the naphthyl and electron-rich aryl groups are compatible and no dearomative intramolecular 6-endo cyclization products were generated, which are in contrast to the previously reported iodinative spirocyclization 7 and CC bond-forming dearomatization, respectively.…”

Asymmetric Dearomatization of 1‐Amino­naphthalene Derivatives through C–C Bond Formation with Electron‐Rich Heterocycles as Nucleophiles

“…N ‐[(Furan‐3‐yl)methyl]‐3‐(2‐methoxyphenyl)‐ N ‐(naphthalen‐1‐yl)propynamide (1a): To a stirred solution of 3‐(2‐methoxyphenyl)prop‐2‐ynoic acid15 (0.706 g, 4.00 mmol) and 4‐methylmorpholine (0.607 g, 6.00 mmol) in tetrahydrofuran (THF, 20 mL) was added isobutyl chloroformate (0.656 g, 4.80 mmol) in THF (3 mL) at 0 °C, and the mixture was stirred at 0 °C for 0.5 h. 1‐Naphthylamine (0.687 g, 4.80 mmol) in THF (2 mL) was added at 0 °C, and the mixture was then stirred at 0 °C for 1 h and at room temperature for 16 h. The reaction was quenched with water, and the resulting mixture was extracted with CH 2 Cl 2 . The organic layer was washed with brine, dried with Na 2 SO 4 , and concentrated to furnish the corresponding crude 3‐(2‐methoxyphenyl)‐ N ‐(naphthalen‐1‐yl)propiolamide11a (1.055 g). A mixture of (furan‐3‐yl)methanol (0.294 g, 3.00 mmol), PPh 3 (1.023 g, 3.90 mmol), and carbon tetrabromide (1.193 g, 3.60 mmol) in CH 2 Cl 2 (15 mL) was stirred at room temperature for 3 h. The mixture was then poured into hexane (200 mL), and the resulting precipitate was removed by vacuum filtration through a pad of Celite.…”

“…3‐Cyclohexyl‐ N ‐[(furan‐3‐yl)methyl]‐ N ‐(naphthalen‐1‐yl)propynamide (1f): By following the procedure used to prepare 1a , 3‐cyclohexylprop‐2‐ynoic acid,11a 1‐naphthylamine, and 3‐(bromomethyl)furan afforded 1f [54 % yield from 3‐cyclohexylprop‐2‐ynoic acid] as an orange solid; m.p. 68.5–70.0 °C.…”

Palladium‐Catalyzed Dearomativesyn‐1,4‐Carboamination with Grignard Reagents

“…[4] Thus,t hese processes have also provided significant advantages in expediting syntheses of natural products and bioactive compounds. Fori nstance,t he catalytic dearomatization of arenes has gained much attention in recent years, [6] whereas the application of such transformations has largely been limited to specific classes of activated arenes such as naphthols, [7] naphthylamines, [8] heteroarenes, [9] and arenes bearing benzylic heteroatoms. Fori nstance,t he catalytic dearomatization of arenes has gained much attention in recent years, [6] whereas the application of such transformations has largely been limited to specific classes of activated arenes such as naphthols, [7] naphthylamines, [8] heteroarenes, [9] and arenes bearing benzylic heteroatoms.…”

“…[5] Nevertheless,d espite these notable advancements in the field, there still remains several challenges to be addressed. Fori nstance,t he catalytic dearomatization of arenes has gained much attention in recent years, [6] whereas the application of such transformations has largely been limited to specific classes of activated arenes such as naphthols, [7] naphthylamines, [8] heteroarenes, [9] and arenes bearing benzylic heteroatoms. [10] Dearomative conversions of simple,n onactivated arenes in ac atalytic manner are rare,e specially the variants which concurrently introduce functionality other than hydrogen.…”