Hammett relation study for the thermal decomposition of sterically hindered hydrogen phthalate esters in solution

Abstract

metal exchange yields 2-picolylsodium, which can couple with 1 to form 13. A first metalation and coupling with 1 leads to 15, where the methine group is a site of choice for further metalation, because of the inductive effect of the picolyl groups. Subsequent coupling forms 16. The increased acidity at the methine group therefore overweighs steric hindrance, since no formation of 17 was observed.

trans‐1‐Sulfonylamino‐2‐isoborneolsulfonylaminocyclohexane Derivatives: Excellent Chiral Ligands for the Catalytic Enantioselective Addition of Organozinc Reagents to Ketones

“…1‐(4′‐Bromophenyl)‐1‐phenyl‐1‐propanol (15 d) :52 Pale yellow oil; R f =0.57 (hexane/AcOEt 4:1); t r (GC)=13.15 min; HPLC (AD, UV 225 nm, hexane/2‐propanol 97:3, flow 1 mL min −1 ): t r (1st)=10.1, t r (2nd)=11.7 min; [ α ] D =+9.9 ( c =1.65 in CH 2 Cl 2 ); er 1st/2nd 10:90; 1 H NMR: δ =0.85 (t, J =7.3 Hz, 3 H; CH 3 ), 2.04 (s, 1 H; OH), 2.26 (q, J =7.2 Hz, 2 H; CH 2 ), 7.15–7.40 ppm (m, 9 H; ArH); 13 C NMR: δ =8.0, 34.25, 78.15, 120.65, 125.95 (2 C), 127.0, 127.95, 128.25, 131 (2 C), 145.85 (2 C), 146.4 ppm (2 C); IR (film): $\tilde \nu $ =3583 (OH), 1483 (CCH), 1005 cm −1 (CO); MS (EI): m / z (%): 293 (<1) [ M +2 H] + , 292 (<1) [ M +H] + , 291 (<1) [ M ] + , 260 (100).…”

“…1‐(4′‐Fluorophenyl)‐1‐phenylethanol (15 g) :52 Pale yellow oil; R f =0.57 (hexane/AcOEt 7:3); t r (GC)=9.29 min; HPLC (AD, UV 217 nm, hexane/2‐propanol 99:1, flow 0.8 mL min −1 ): t r (1st)=37.9, t r (2nd)=39.4 min; [ α ] D =−4.9 ( c =1.06, CHCl 3 ; er 1st/2nd 92:8; 1 H NMR: δ =1.92 (s, 3 H; CH 3 ), 2.15 (s, 1 H; OH), 6.95–7.0, 7.20–7.40 ppm (2 m, 5 H, 4 H; ArH); 13 C NMR: δ =31.0, 75.8, 114.8 (d, 2 J (C,F)=20.9 Hz), 125.7 (2 C), 127.1 (2 C), 127.6 (d, 3 J (C,F)=7.7 Hz), 128.2 (2 C), 143.8 (d, 4 J (C,F)=3.3 Hz), 147.7, 161.7 ppm (d, 1 J (C,F)=244.8 Hz); IR (film): $\tilde \nu $ =3431 (OH), 1518 cm −1 (CCH); MS (EI): m / z (%): 216 (5) [ M ] + , 201 (100).…”

“…-Chlorophenyl)-1-phenylethanol (15 f):[52] Pale yellow oil; R f = 0.59 (hexane/AcOEt 7:3); t r (GC) = 11.02 min; HPLC (AD, UV 225 nm, hexane/2-propanol 99:1, flow 1 mL min À1 ): t r (1st) = 35.7, t r (2nd) = 40.6 min; [a] D = À5.3 (c = 0.2, CHCl 3 ); er 1st/2nd 44:56; 1 H NMR: d = 1.90 (s, 3 H; CH 3 ), 2.28 (s, 1 H; OH), 7.20-7.40 ppm (m, 9 H; ArH); 13 C NMR: d = 30.7, 30.8, 75.8, 125.7 (2 C), 127.15, 127.3 (2 C), 128.2 (2 C), 128.25 (2 C), 132.65, 146.5, 147.4 ppm; IR (film): ñ = 3416 (OH), 1502 cm À1 (C=CH); MS (EI): m/z (%): 233 (1) [M+H] + , 232 (7) [M] + , 217 (100).…”

“…1-(4'-Fluorophenyl)-1-phenylethanol (15 g):[52] Pale yellow oil; R f = 0.57 (hexane/AcOEt 7:3); t r (GC) = 9.29 min; HPLC (AD, UV 217 nm, hexane/2-propanol 99:1, flow 0.8 mL min À1 ): t r (1st) = 37.9, t r (2nd) =39.4 min; [a] D = À4.9 (c = 1.06, CHCl 3 ; er 1st/2nd 92:8; 1 H NMR: d = 1.92 (s, 3 H; CH 3 ), 2.15 (s, 1 H; OH), 6.95-7.0, 7.20-7.40 ppm (2 m, 5 H, 4 H; ArH); 13 C NMR: d = 31.0, 75.8, 114.8 (d, 2 JA C H T U N G T R E N N U N G (C,F) = 20.9 Hz), 125.7 (2 C), 127.1 (2 C), 127.6 (d, 3 JA C H T U N G T R E N N U N G (C,F) = 7.7 Hz), 128.2 (2 C), 143.8 (d, 4 JA C H T U N G T R E N N U N G (C,F) = 3.3 Hz), 147.7, 161.7 ppm (d, 1 JA C H T U N G T R E N N U N G (C,F) = 244.8 Hz); IR (film): ñ = 3431 (OH), 1518 cm À1 (C=CH); MS (EI): m/z (%): 216 (5) [M] + , 201 (100). General procedure for the enantioselective allylation of acetophenone (12 a): A solution of [PdA C H T U N G T R E N N U N G (PPh 3 ) 4 ] (11.5 mg, 0.01 mmol, 0.01 equiv), either allyl carbonate (21 a, 0.43 mL, 3 mmol, 3 equiv) or cynnamyl acetate (21 b, 1.0 mL, 6 mmol, 6 equiv), and diethylzinc (1.1 m in toluene, 8.2 mL, 9 mmol, 9 equiv) was stirred at 70 8C for 16 h in a pressure tube under an argon atmosphere.…”