ChemInform Abstract: Synergistic Rhodium/Phosphoric Acid Catalysis for the Enantioselective Addition of Oxonium Ylides to ortho‐Quinone Methides.

Abstract

A novel and highly stereoselective method for the domino‐type reaction of diazoesters with in situ generated ortho‐quinone methides to furnish functionalized benzofuran derivatives with three contiguous stereogenic centers is reported.

Catalytic Asymmetric [4 + 2] Cycloaddition of ortho-Alkenyl Naphthols/Phenols with ortho-Quinone Methides: Highly Stereoselective Synthesis of Chiral 2,3,4-Trisubstituted Chromans

“…Solvents were dried by standard methods and distilled under argon. 1 H, 13 C NMR, and 19 F NMR spectra were recorded on 400 MHz or 600 MHz instruments using CDCl 3 , acetone-d 6 , or DMSO-d 6 as solvents. Chemical shifts of 1 H NMR were recorded in parts per million (ppm, δ) relative to tetramethylsilane (δ = 0.00 ppm) with the solvent resonance as an internal standard (CDCl 3 : δ = 7.26 ppm, acetone-d 6 : δ = 2.05 ppm, and DMSO-d 6 : δ = 2.50 ppm).…”

“…1 H NMR (600 MHz, CDCl 3 , ppm): δ 7.86 (d, J = 8.5 Hz, 1H), 7.75 (d, J = 8.1 Hz, 1H), 7.68 (d, J = 8.9 Hz, 1H), 7.54 (s, 1H), 7.46−7.43 (m, 1H), 7.41−7.37 (m, 2H), 7.35−7.32 (m, 1H), 7.32−7.26 (m, 2H), 7.17 (d, J = 8.9 Hz, 1H), 6.94 (d,J = 16.7 Hz,1H),5.73 (br,1H). 13 C{ 1 H} NMR (150 MHz, CDCl 3 , ppm): δ 150. 7, 138.6, 134.8, 134.3, 132.7, 130.0, 129.6, 128.9, 128.4, 128.1, 126.8, 126.3, 124.8, 123.6, 123.5, 117.7, 116.3 (E)-1-(2-Methylstyryl)naphthalen-2-ol (1e).…”

“…1 H NMR (600 MHz, CDCl 3 , ppm): δ 7.89 (d,J = 8.4 Hz,1H),7.75 (d,J = 8.1 Hz,1H),7.72 (d,J = 7.3 Hz,1H),7.69 (d,J = 8.9 Hz,1H),1H),1H),2H),1H),1H),1H), 5.88 (s, 1H), 2.37 (s, 3H). 13 C{ 1 H} NMR (150 MHz, CDCl 3 , ppm): δ 150. 6, 135.8, 135.7, 134.0, 132.9, 130.6, 129.3, 128.9, 128.4, 126.6, 126.4, 125.5, 123.7, 123.5, 123.3, 117.6, 117.0, 19.9.…”

“…1 H NMR (600 MHz, CDCl 3 , ppm): δ 7.91 (d,J = 8.4 Hz,1H),4H),2H),7.69 (d,J = 8.9 Hz,1H),4H), 7.33 (t, J = 7.8 Hz, 1H), 7.21 (d, J = 8.9 Hz, 1H), 7.14 (d,J = 16.7 Hz,1H), 5.84 (s, 1H). 13 C{ 1 H} NMR (150 MHz, CDCl 3 , ppm): δ 150. 7, 136.0, 134.1, 133.6, 133.3, 132.9, 129.4, 129.0, 128.5, 128.4, 128.1, 127.7, 126.8, 126.7, 126.5, 126.3, 123.7, 123.5, 123.2, 122.3, 117.7, 116.8.…”

“…1 H NMR (600 MHz, CDCl 3 , ppm): δ 7.88 (d,J = 8.5 Hz,1H),7.73 (d,J = 8.0 Hz,1H),7.65 (d,J = 8.8 Hz,1H),3H),3H),7.24 (t,J = 7.4 Hz,1H),7.16 (d,J = 8.9 Hz,1H),1H),6.97 (d,J = 16.0 Hz, 1H), 6.86−6.82 (m, 1H), 6.63 (d, J = 15.6 Hz, 1H), 5.69 (s, 1H). 13 C{ 1 H} NMR (150 MHz, CDCl 3 , ppm): δ 150. 7, 136.9, 136.2, 133.8, 132.6, 129.3, 128.72, 128.69, 128.4, 127.9, 126.63, 126.56, 125.5, 123.6, 123.5, 117.7, 116.8 271.1128; found, 271.1127.…”